A |  B |  C |  D |  E |  F |  G |  H |  I |  J |  K |  L |  M |  N |  O |  P |  Q |  R |  S |  T |  U |  V |  W |  X |  Y |  Z

The Medical Terminology and Drug Database is provided as a convenience to our users. Definitions are provided by the National Cancer Institute, U.S. National Institutes of Health, for informational purposes only. This list is updated monthly.

P

P-32

A radioactive form of phosphorus used in the treatment of cancer.

PALA

A substance that is being studied for its ability to increase the effectiveness of the anticancer drug fluorouracil.

PAP

Prostatic acid phosphatase. An enzyme produced by the prostate. It may be found in increased amounts in men who have prostate cancer.

PCA

Patient-controlled analgesia. A method in which the patient controls the amount of pain medicine that is used. When pain relief is needed, the person can receive a preset dose of pain medicine by pressing a button on a computerized pump that is connected to a small tube in the body.

PCR

Polymerase chain reaction. A laboratory method used to make many copies of a specific DNA sequence.

PDQ

Physician Data Query. PDQ is an online database developed and maintained by the National Cancer Institute. Designed to make the most current, credible, and accurate cancer information available to health professionals and the public, PDQ contains peer-reviewed summaries on cancer treatment, screening, prevention, genetics, complementary and alternative medicine, and supportive care; a registry of cancer clinical trials from around the world; and directories of physicians, professionals who provide genetics services, and organizations that provide cancer care. Most of this information, and more specific information about PDQ, can be found on the NCI's Web site at http://www.cancer.gov/cancertopics/pdq.

PEG-Intron

A drug used to treat hepatitis C infections. It is also being studied in the treatment and prevention of cancer. It is a cytokine that is modified in the laboratory. It belongs to the family of drugs called biological response modifiers. Also called PEG-interferon alfa-2b and SCH 54031.

PEG-MGDF

A form of megakaryocyte growth and development factor (MGDF) that is made in the laboratory. MGDF comes from the protein thrombopoietin, which is normally made in the body to help make platelets. PEG-MGDF is being studied as a way to increase the number of platelets in patients receiving chemotherapy. Also called polyethylene glycosylated recombinant human megakaryocyte growth and development factor (PEG-rhMGDF).

PEG-interferon alfa-2a

A drug used to treat hepatitis C infections. It is also being studied in the treatment and prevention of cancer. It is a cytokine that is modified in the laboratory. It belongs to the family of drugs called biological response modifiers. Also called Pegasys.

PEG-interferon alfa-2b

A drug used to treat hepatitis C infections. It is also being studied in the treatment and prevention of cancer. It is a cytokine that is modified in the laboratory. It belongs to the family of drugs called biological response modifiers. Also called PEG-Intron and SCH 54031.

PEG-rhMGDF

Polyethylene glycosylated recombinant human megakaryocyte growth and development factor. A form of megakaryocyte growth and development factor (MGDF) that is made in the laboratory. MGDF comes from the protein thrombopoietin, which is normally made in the body to help make platelets. PEG-rhMGDF is being studied as a way to increase the number of platelets in patients receiving chemotherapy. Also called PEG-MGDF.

PEITC

Phenethyl isothiocyanate. A substance that is being studied in the prevention of cancer. It is a naturally occurring compound found in some cruciferous vegetables.

PET scan

Positron emission tomography scan. A procedure in which a small amount of radioactive glucose (sugar) is injected into a vein, and a scanner is used to make detailed, computerized pictures of areas inside the body where the glucose is used. Because cancer cells often use more glucose than normal cells, the pictures can be used to find cancer cells in the body.

PI-88

A substance that is being studied in the treatment of cancer. It belongs to the family of drugs called antiangiogenesis agents.

PIN

Prostatic intraepithelial neoplasia. Noncancerous growth of cells lining the internal and external surfaces of the prostate gland. Having high-grade PIN may increase the risk of developing prostate cancer.

PJS

Peutz-Jeghers syndrome. A genetic disorder in which polyps form in the intestine and dark spots appear on the mouth and fingers. Having PJS increases the risk of developing gastrointestinal and many other types of cancer.

PKC

Protein kinase C. An enzyme found throughout the body's tissues and organs. Several forms of PKC are involved in many cellular functions. PKC is being studied in the treatment of cancer.

PKC412

A substance that is being studied in the treatment of cancer. It belongs to the families of drugs called protein kinase C (PKC) and protein tyrosine kinase inhibitors.

PLL

Prolymphocytic leukemia. A type of chronic lymphocytic leukemia (CLL) in which too many immature white blood cells (prolymphocytes) are found in the blood and bone marrow. PLL usually progresses more rapidly than classic CLL.

PN401

A substance that is being studied for its ability to protect against the gastrointestinal side effects caused by fluorouracil. Also called triacetyluridine. It belongs to the family of drugs called cytoprotective agents.

PNET

Primitive neuroectodermal tumor. One of a group of cancers that develop from the same type of early cells, and share certain biochemical and genetic features. Some PNETs develop in the brain and central nervous system (CNS-PNET), and others develop in sites outside of the brain such as the limbs, pelvis, and chest wall (peripheral PNET).

PNH

Paroxysmal nocturnal hemoglobinuria. A rare disorder in which red blood cells are easily destroyed by certain immune system proteins. Symptoms include blood clots, and red or brownish urine in the morning. Aplastic anemia (decreased production of blood cells) may lead to PNH, and people with PNH are at increased risk of acute myelogenous leukemia.

PNU 166148

A substance that is being studied in the treatment of cancer. It belongs to the family of drugs called topoisomerase inhibitors.

PNU-93914

A form of the anticancer drug paclitaxel that may have fewer side effects and work better than paclitaxel. It is being studied in the treatment of cancer. It belongs to the family of drugs called mitotic inhibitors. Also called LEP-ETU and paclitaxel liposome.

PR+

Progesterone receptor positive. Breast cancer cells that have a protein (receptor molecule) to which progesterone will attach. Breast cancer cells that are PR+ need the hormone progesterone to grow and will usually respond to hormonal therapy.

PR-

Progesterone receptor negative. Breast cancer cells that do not have a protein (receptor molecule) to which progesterone will attach. Breast cancer cells that are PR- do not need the hormone progesterone to grow and usually do not respond to hormonal therapy.

PS-341

A drug that is used to treat multiple myeloma and is being studied in the treatment of other types of cancer. It belongs to the families of drugs called proteosome inhibitors and dipeptidyl boronic acids. Also called Velcade and bortezomib.

PSA

Prostate-specific antigen. A substance produced by the prostate that may be found in an increased amount in the blood of men who have prostate cancer, benign prostatic hyperplasia, or infection or inflammation of the prostate.

PSC 833

A substance that is being studied for its ability to prevent or overcome the resistance of tumor cells to some anticancer drugs. It belongs to the family of drugs called cyclosporine analogs.

PTC

Percutaneous transhepatic cholangiography (per-kyoo-TAN-ee-us trans-heh-PAT-ik ko-LAN-jee-AH-gra-fee). A procedure to x-ray the hepatic and common bile ducts. A contrasting agent is injected into the liver or bile duct, and the ducts are then x-rayed to find the point of obstruction.

PTCD

Percutaneous transhepatic cholangiodrainage. A procedure to drain bile to relieve pressure in the bile ducts caused by a blockage. An x-ray of the liver and bile ducts locates the blockage of bile flow. Images made by ultrasound guide placement of a stent (tube), which remains in the liver. Bile drains through the stent into the small intestine or into a collection bag outside the body. This procedure may relieve jaundice before surgery. Also called percutaneous transhepatic biliary drainage.

PTH

A substance made by the parathyroid gland that helps the body store and use calcium. Also called parathormone, parathyroid hormone, or parathyrin.

PTK787/ZK 222584

A substance that is being studied in the treatment of cancer. It belongs to the families of drugs called protein tyrosine kinase inhibitors and VEGF receptor kinase inhibitors. Also called vatalanib.

PTSD

Post-traumatic stress disorder. An anxiety disorder that develops in reaction to physical injury or severe mental or emotional distress, such as military combat, violent assault, natural disaster, or other life-threatening events. Having cancer may also lead to PTSD. Symptoms interfere with day-to-day living and include reliving the event in nightmares or flashbacks; avoiding people, places, and things connected to the event; feeling alone and losing interest in daily activities; and having trouble concentrating and sleeping.

PUVA therapy

Psoralen and ultraviolet A therapy. A type of photodynamic therapy used to treat skin conditions such as psoriasis, vitiligo, and skin nodules of cutaneous T-cell lymphoma. The patient receives psoralen (a drug that becomes active when it is exposed to light) by mouth or applied to the skin, followed by ultraviolet A radiation. PUVA therapy may increase the risk of getting skin cancer.

PV701

A virus that is being studied in the treatment of cancer. It belongs to the family of viruses that cause Newcastle disease in birds.

Paget's disease of bone

A chronic condition in which both the breakdown and regrowth of bone are increased. Paget's disease of bone occurs most frequently in the pelvic and leg bones, skull, and lower spine. It is most common in older individuals, and may lead to bone pain, deformities, and fractures. Also called osteitis deformans.

Paget's disease of the nipple

A form of breast cancer in which the tumor grows from ducts beneath the nipple onto the surface of the nipple. Symptoms commonly include itching and burning and an eczema-like condition around the nipple, sometimes accompanied by oozing or bleeding.

Pancoast tumor

A type of lung cancer that begins in the upper part of a lung and spreads to nearby tissues such as the ribs and vertebrae. Most Pancoast tumors are non-small cell cancers. Also called pulmonary sulcus tumor.

Pancoast's tumor

Non-small cell lung cancer that originates in the upper portion of the lung and extends to other nearby tissues such as the ribs and vertebrae. Also called a pulmonary sulcus tumor.

Pap smear

A procedure in which cells are scraped from the cervix for examination under a microscope. It is used to detect cancer and changes that may lead to cancer. A Pap smear can also show noncancerous conditions, such as infection or inflammation. Also called a Pap test.

Pap test

A procedure in which cells are scraped from the cervix for examination under a microscope. It is used to detect cancer and changes that may lead to cancer. A Pap test can also show noncancerous conditions, such as infection or inflammation. Also called a Pap smear.

Parkinson's disease

A progressive disorder of the nervous system marked by muscle tremors, muscle rigidity, decreased mobility, stooped posture, slow voluntary movements, and a mask-like facial expression.

Paterson-Kelly syndrome

A disorder marked by anemia caused by iron deficiency, and a web-like growth of membranes in the throat that makes swallowing difficult. Having Paterson-Kelly syndrome may increase the risk of developing esophageal cancer. Also called Plummer-Vinson syndrome and sideropenic dysphagia.

Paxil

A drug used to treat depression and anxiety disorders. It belongs to the family of drugs called selective serotonin reuptake inhibitors (SSRI). Also called paroxetine hydrochloride.

Pegasys

A drug used to treat hepatitis C infections. It is also being studied in the treatment and prevention of cancer. It is a cytokine that is modified in the laboratory. It belongs to the family of drugs called biological response modifiers. Also called PEG-interferon alfa-2a.

Peutz-Jeghers syndrome

PJS. A genetic disorder in which polyps form in the intestine and dark spots appear on the mouth and fingers. Having PJS increases the risk of developing gastrointestinal and many other types of cancer.

Philadelphia chromosome

An abnormality of chromosome 22 in which part of chromosome 9 is transferred to it. Bone marrow cells that contain the Philadelphia chromosome are often found in chronic myelogenous leukemia.

Photofrin

A drug used to treat some types of cancer. When absorbed by cancer cells and exposed to light, porfimer sodium becomes active and kills the cancer cells. It belongs to the family of drugs called photodynamic therapy agents. Also called porfimer sodium.

Physician Data Query

PDQ. The Physician Data Query is an online database developed and maintained by the National Cancer Institute. Designed to make the most current, credible, and accurate cancer information available to health professionals and the public, PDQ contains peer-reviewed summaries on cancer treatment, screening, prevention, genetics, complementary and alternative medicine, and supportive care; a registry of cancer clinical trials from around the world; and directories of physicians, professionals who provide genetics services, and organizations that provide cancer care. Most of this information, and more specific information about PDQ, can be found on the NCI's Web site at http://www.cancer.gov/cancertopics/pdq.

Piritrexim

A substance that is being studied in the treatment of cancer. It belongs to the family of drugs called folate antagonists.

Plenaxis

A drug used to reduce the amount of testosterone made in patients with advanced symptomatic prostate cancer for which no other treatment options are available. It belongs to the family of drugs called gonadotropin-releasing hormone (GnRH) antagonists. Also called abarelix.

Plummer-Vinson syndrome

A disorder marked by anemia caused by iron deficiency, and a web-like growth of membranes in the throat that makes swallowing difficult. Having Plummer-Vinson syndrome may increase the risk of developing esophageal cancer. Also called Paterson-Kelly syndrome and sideropenic dysphagia.

Polyphenon® E

A substance that is being studied in the prevention of cancer. It is made from decaffeinated green tea, and contains chemicals called catechins, which are antioxidants. Also called green tea extract.

Polyphenon® E

A substance that is being studied in the prevention of cancer. It is made from decaffeinated green tea, and contains chemicals called catechins, which are antioxidants. Also called green tea extract.

Post-traumatic stress disorder

PTSD. An anxiety disorder that develops in reaction to physical injury or severe mental or emotional distress, such as military combat, violent assault, natural disaster, or other life-threatening events. Having cancer may also lead to PTSD. Symptoms interfere with day-to-day living and include reliving the event in nightmares or flashbacks; avoiding people, places, and things connected to the event; feeling alone and losing interest in daily activities; and having trouble concentrating and sleeping.

Pravachol

A drug that lowers the amount of cholesterol in the blood. It may also make tumor cells more sensitive to anticancer drugs, and is being studied in the treatment of cancer. It belongs to the families of drugs called HMG-CoA reductase inhibitors (statins) and chemosensitizers. Also called pravastatin.

Prost 30

A monoclonal antibody that is being studied in the detection and treatment of cancer. Monoclonal antibodies are produced in the laboratory and can locate and bind to cancer cells.

Prost 30 monoclonal antibody

A type of monoclonal antibody used in cancer detection or therapy. Monoclonal antibodies are laboratory-produced substances that can locate and bind to cancer cells.

Purinethol

A drug used to treat acute lymphatic leukemia. It belongs to the family of drugs called antimetabolites. Also called mercaptopurine.

p-value

A statistics term. A measure of probability that a difference between groups during an experiment happened by chance. For example, a p-value of .01 (p = .01) means there is a 1 in 100 chance the result occurred by chance. The lower the p-value, the more likely it is that the difference between groups was caused by treatment.

p53 gene

A tumor suppressor gene that normally inhibits the growth of tumors. This gene is altered in many types of cancer.

pM-81

A monoclonal antibody that is being studied in the detection and treatment of cancer. Monoclonal antibodies are produced in the laboratory and can locate and bind to cancer cells.

pM-81 monoclonal antibody

A type of monoclonal antibody used in cancer detection or therapy. Monoclonal antibodies are laboratory-produced substances that can locate and bind to cancer cells.

pack year

A way to measure the amount a person has smoked over a long period of time. It is calculated by multiplying the number of packs of cigarettes smoked per day by the number of years the person has smoked. For example, 1 pack year is equal to smoking 1 pack per day for 1 year, or 2 packs per day for half a year, and so on.

paclitaxel

A drug that is used to treat cancer. It belongs to the family of drugs called mitotic inhibitors.

paclitaxel liposome

A form of the anticancer drug paclitaxel that may have fewer side effects and work better than paclitaxel. It is being studied in the treatment of cancer. It belongs to the family of drugs called mitotic inhibitors. Also called LEP-ETU and PNU-93914.

pain threshold

The point at which a person becomes aware of pain.

palate

The roof of the mouth. The front portion is bony (hard palate), and the back portion is muscular (soft palate).

palatine uvula

The soft flap of tissue that hangs down at the back of the mouth (at the edge of the soft palate). Also called uvula.

palliative care

Care given to improve the quality of life of patients who have a serious or life-threatening disease. The goal of palliative care is to prevent or treat as early as possible the symptoms of the disease, side effects caused by treatment of the disease, and psychological, social, and spiritual problems related to the disease or its treatment. Also called comfort care, supportive care, and symptom management.

palliative therapy

Treatment given to relieve the symptoms and reduce the suffering caused by cancer and other life-threatening diseases. Palliative cancer therapies are given together with other cancer treatments, from the time of diagnosis, through treatment, survivorship, recurrent or advanced disease, and at the end of life.

palmar-plantar erythodysthesia

A condition marked by pain, swelling, numbness, tingling, or redness of the hands or feet. It sometimes occurs as a side effect of certain anticancer drugs. Also known as hand-foot syndrome.

palpable disease

A term used to describe cancer that can be felt by touch, usually present in lymph nodes, skin, or other organs of the body such as the liver or colon.

palpation

Examination by pressing on the surface of the body to feel the organs or tissues underneath.

pamidronate

A drug that is used to treat hypercalcemia (too much calcium in the blood) and cancer that has spread to the bones. It belongs to the family of drugs called bisphosphonates.

panacea

A cure-all.

pancreas

A glandular organ located in the abdomen. It makes pancreatic juices, which contain enzymes that aid in digestion, and it produces several hormones, including insulin. The pancreas is surrounded by the stomach, intestines, and other organs.

pancreatectomy

Surgery to remove all or part of the pancreas. In a total pancreatectomy, part of the stomach, part of the small intestine, the common bile duct, gallbladder, spleen, and nearby lymph nodes also are removed.

pancreatic

Having to do with the pancreas.

pancreatic cancer

A disease in which malignant (cancer) cells are found in the tissues of the pancreas. Also called exocrine cancer.

pancreatic duct

Part of a system of ducts in the pancreas. Pancreatic juices containing enzymes are released into these ducts and flow into the small intestine.

pancreatic enzyme

A protein secreted by the pancreas that aids in the digestion of food.

pancreatic juice

Fluid made by the pancreas. Pancreatic juices contain proteins called enzymes that aid in digestion.

pancreatitis

Inflammation of the pancreas. Chronic pancreatitis may cause diabetes and problems with digestion. Pain is the primary symptom.

panitumumab

A monoclonal antibody that is being studied in the diagnosis and treatment of some types of cancer. Monoclonal antibodies are made in the laboratory and can locate and bind to cancer cells. Also called ABX-EGF.

papillary serous carcinoma

An aggressive cancer that usually affects the uterus/endometrium, peritoneum, or ovary.

papillary thyroid cancer

Cancer that forms in cells in the thyroid and grows in small finger-like shapes. It grows slowly, is more common in women than in men, and often occurs before age 40. It is the most common type of thyroid cancer.

papillary tumor

A tumor shaped like a small mushroom, with its stem attached to the epithelial layer (inner lining) of an organ.

papilledema

Swelling around the optic disk, the area where the optic nerve (the nerve that carries messages from the eye to the brain) enters the eyeball. Papilledema occurs when increased brain pressure caused by tumors or other problems results in swelling of the optic nerve.

paracentesis

A procedure in which a thin needle or tube is put into the abdomen to remove fluid from the peritoneal cavity (the space within the abdomen that contains the intestines, the stomach, and the liver).

paraganglia

A collection of cells that came from embryonic nervous tissue, and are found near the adrenal glands and some blood vessels and nerves. Most paraganglia secrete epinephrine and norepinephrine.

paraganglioma

A rare, usually benign tumor that develops from cells of the paraganglia. Paraganglia are a collection of cells that came from embryonic nervous tissue, and are found near the adrenal glands and some blood vessels and nerves. Paragangliomas that develop in the adrenal gland are called pheochromocytomas. Those that develop outside of the adrenal glands near blood vessels or nerves are called glomus tumors or chemodectomas.

parageusia

A bad taste in the mouth. Also called dysgeusia.

paralysis

Loss of ability to move all or part of the body.

paramyxovirus

A type of virus that has hemagglutinin-neuraminidase proteins in the outer coat and RNA as the genetic material. Measles (rubeola) virus, mumps virus, and Newcastle disease virus are paramyxoviruses.

paraneoplastic syndrome

A group of symptoms that may develop when substances released by some cancer cells disrupt the normal function of surrounding cells and tissue.

parasite

An animal or plant that gets nutrients by living on or in an organism of another species. A complete parasite gets all of its nutrients from the host organism, but a semi-parasite gets only some of its nutrients from the host.

parasitic

Having to do with or being a parasite (an animal or plant that gets nutrients by living on or in an organism of another species).

parathormone

A substance made by the parathyroid gland that helps the body store and use calcium. Also called parathyroid hormone, parathyrin, or PTH.

parathyrin

A substance made by the parathyroid gland that helps the body store and use calcium. Also called parathormone, parathyroid hormone, or PTH.

parathyroid gland

One of four pea-sized glands found on the thyroid. The parathyroid hormone produced by these glands increases the calcium level in the blood.

parathyroid hormone

A substance made by the parathyroid gland that helps the body store and use calcium. Also called parathormone, parathyrin, or PTH.

parenchyma

The essential or functional elements of an organ.

parenteral nutrition

A form of nutrition that is delivered into a vein. Parenteral nutrition does not use the digestive system. It may be given to people who are unable to absorb nutrients through the intestinal tract because of vomiting that won't stop, severe diarrhea, or intestinal disease. It may also be given to those undergoing high-dose chemotherapy or radiation and bone marrow transplantation. It is possible to give all of the protein, calories, vitamins and minerals a person needs using parenteral nutrition. Also known as hyperalimentation or total parenteral nutrition (TPN).

paresthesias

Abnormal touch sensations, such as burning or prickling, that occur without an outside stimulus.

paricalcitol

A substance that is being used to treat overactive parathyroid glands in patients with kidney failure. It is also being studied in the treatment of cancer. Paricalcitol belongs to the family of drugs called vitamin D analogs.

parietal pericardium

The outer layer of the pericardium, which is a thin sac of tissue that surrounds the heart.

parietal peritoneum

The layers of tissue that line the abdominal wall and the pelvic cavity.

parotidectomy

Surgery to remove all or part of the parotid gland (a large salivary gland located in front of and just below the ear). In a radical parotidectomy, the entire gland is removed.

paroxetine hydrochloride

A drug used to treat depression and anxiety disorders. It belongs to the family of drugs called selective serotonin reuptake inhibitors (SSRI). Also called Paxil.

paroxysmal nocturnal hemoglobinuria

PNH. A rare disorder in which red blood cells are easily destroyed by certain immune system proteins. Symptoms include blood clots, and red or brownish urine in the morning. Aplastic anemia (decreased production of blood cells) may lead to PNH, and people with PNH are at increased risk of acute myelogenous leukemia.

partial cystectomy

The removal of the cancer as well as some of the bladder tissue around the tumor. Also called segmental cystectomy.

partial hysterectomy

Surgery to remove the uterus only. When the uterus and part or all of the cervix are removed, it is called a total hysterectomy.

partial laryngectomy

An operation to remove part of the larynx (voice box).

partial mastectomy

The removal of cancer as well as some of the breast tissue around the tumor and the lining over the chest muscles below the tumor. Usually some of the lymph nodes under the arm are also taken out. Also called segmental mastectomy.

partial nephrectomy

Surgery to remove part of one kidney or a kidney tumor, but not an entire kidney.

partial oophorectomy

Surgery to remove part of one ovary or part of both ovaries.

partial remission

A decrease in the size of a tumor, or in the extent of cancer in the body, in response to treatment. Also called partial response.

partial response

A decrease in the size of a tumor, or in the extent of cancer in the body, in response to treatment. Also called partial remission.

passive antibody therapy

Treatment with injections of antibodies made in another animal or in the laboratory.

pathologic fracture

A broken bone caused by disease, often by the spread of cancer to the bone.

pathological staging

A method used to determine the stage of cancer. Tissue samples are removed during surgery or a biopsy. The stage is determined based on how the cells in the samples look under a microscope.

pathologist

A doctor who identifies diseases by studying cells and tissues under a microscope.

pathology report

The description of cells and tissues made by a pathologist based on microscopic evidence, and sometimes used to make a diagnosis of a disease.

patient advocate

A person who helps a patient work with others who have an effect on the patient's health, including doctors, insurance companies, employers, case managers, and lawyers. A patient advocate helps resolve issues about health care, medical bills, and job discrimination related to a patient's medical condition. Cancer advocacy groups try to raise public awareness about important cancer issues, such as the need for cancer support services, education, and research. Such groups work to bring about change that will help cancer patients and their families.

patient-controlled analgesia

PCA. A method in which the patient controls the amount of pain medicine that is used. When pain relief is needed, the person can receive a preset dose of pain medicine by pressing a button on a computerized pump that is connected to a small tube in the body.

peau d'orange

A dimpled condition of the skin of the breast, resembling the skin of an orange, sometimes found in inflammatory breast cancer.

pediatric

Having to do with children.

pediatric hematologist

A doctor who specializes in treating blood disorders in children.

pediatric nurse specialist

A registered nurse with an advanced degree in nursing who specializes in the care of children.

pediatric surgeon

A surgeon who specializes in the treatment of children. A surgeon removes or repairs a part of the body by operating on the patient.

pedigree

A record of one's ancestors, offspring, siblings, and their offspring that may be used to determine the pattern of certain genes or disease inheritance within a family.

pegaspargase

A modified form of asparaginase, an anticancer drug that belongs to the family of drugs derived from enzymes.

pegfilgrastim

A drug used to increase numbers of white blood cells in patients who are receiving chemotherapy. It belongs to the family of drugs called colony-stimulating factors. Also called Neulasta and filgrastim-SD/01.

peldesine

A substance that is being studied for the treatment of cancer.

pelvic

Having to do with the pelvis (the lower part of the abdomen located between the hip bones).

pelvic exam

A physical examination of the vagina, cervix, uterus, fallopian tubes, ovaries, and rectum.

pelvic exenteration

Surgery to remove the lower colon, rectum, and bladder, and create stomata (openings) through which urine and stool are passed out of the body. In women, the cervix, vagina, ovaries, and nearby lymph nodes are also removed.

pelvic lymphadenectomy

Surgery to remove lymph nodes in the pelvis for examination under a microscope to see if they contain cancer.

pelvic wall

The muscles and ligaments that line the part of the body between the hips.

pelvis

The lower part of the abdomen, located between the hip bones.

pemetrexed disodium

A drug that is used to treat malignant pleural mesothelioma and advanced non-small cell lung cancer and is being studied in the treatment of other types of cancer. It belongs to the family of drugs called enzyme inhibitors. Also called Alimta and LY231514.

penclomedine

A substance that is being studied in the treatment of cancer. It belongs to the family of drugs called alkylating agents.

penetrance

A characteristic of a genotype; it refers to the likelihood that a clinical condition will occur when a particular genotype is present.

penicillamine

A drug that removes copper from the body and is used to treat diseases in which there is an excess of copper. It is also being studied as a possible angiogenesis inhibitor in the treatment of brain tumors.

penicillin

A drug that is used to treat infection. It belongs to the family of drugs called antibiotics.

penile implant

A firm rod or inflatable device that is placed in the penis during a surgical procedure. The implant makes it possible to have and keep an erection. Penile implants are used to treat erectile dysfunction or impotence.

penis

An external male reproductive organ. It contains a tube called the urethra, which carries semen and urine to the outside of the body.

pentetic acid calcium

A drug that protects healthy tissues from the toxic effects of anticancer drugs.

pentosan polysulfate

A drug used to relieve pain or discomfort associated with chronic inflammation of the bladder. It is also being evaluated for its protective effects on the gastrointestinal tract in people undergoing radiation therapy.

pentostatin

An anticancer drug that belongs to the family of drugs called antimetabolites.

pentoxifylline

A drug used to prevent blood clotting and as a treatment that may help decrease weight loss in people with cancer.

peptide

Any compound consisting of two or more amino acids, the building blocks of proteins.

peptide 946

A protein that causes white blood cells to recognize and destroy melanoma cells.

percutaneous ethanol injection

An injection of ethanol (alcohol) through the skin directly into the tumor to kill cancer cells.

percutaneous transhepatic biliary drainage

A procedure to drain bile to relieve pressure in the bile ducts caused by a blockage. An x-ray of the liver and bile ducts locates the blockage of bile flow. Images made by ultrasound guide placement of a stent (tube), which remains in the liver. Bile drains through the stent into the small intestine or into a collection bag outside the body. This procedure may relieve jaundice before surgery. Also called percutaneous transhepatic cholangiodrainage (PTCD).

percutaneous transhepatic cholangiodrainage

PTCD. A procedure to drain bile to relieve pressure in the bile ducts caused by a blockage. An x-ray of the liver and bile ducts locates the blockage of bile flow. Images made by ultrasound guide placement of a stent (tube), which remains in the liver. Bile drains through the stent into the small intestine or into a collection bag outside the body. This procedure may relieve jaundice before surgery. Also called percutaneous transhepatic biliary drainage.

percutaneous transhepatic cholangiography

PTC. A procedure to x-ray the hepatic and common bile ducts. A contrasting agent is injected into the liver or bile duct, and the ducts are then x-rayed to find the point of obstruction.

performance status

A measure of how well a patient is able to perform ordinary tasks and carry out daily activities.

perfusion

Bathing an organ or tissue with a fluid. In regional perfusion, a specific area of the body (usually an arm or a leg) receives high doses of anticancer drugs through a blood vessel. Such a procedure is performed to treat cancer that has not spread.

perfusion magnetic resonance imaging

A special type of magnetic resonance imaging (MRI) that uses an injected dye in order to see blood flow through tissues. Also called magnetic resonance perfusion imaging.

pericardial effusion

An abnormal collection of fluid inside the sac that covers the heart.

perifosine

A substance that is being studied in the treatment of cancer. It belongs to the family of drugs called alkylphospholipids.

perillyl alcohol

A substance that is being studied in the prevention of cancer. It belongs to the family of plant drugs called monoterpenes.

perimenopausal

The time of a woman's life when menstrual periods become irregular. Refers to the time near menopause.

perineal colostomy

An opening made surgically to allow the colon to exit the body through the perineum (the area of the body between the anus and the vulva in females, and between the anus and the scrotum in males). A colostomy provides a new path for waste material to leave the body after part of the colon has been removed.

perineal prostatectomy

Surgery to remove the prostate through an incision made between the scrotum and the anus.

perineum

The area of the body between the anus and the vulva in females, and between the anus and the scrotum in males.

perineural

Around a nerve or group of nerves.

perioperative

Around the time of surgery. This usually lasts from the time the patient goes into the hospital or doctor's office for surgery until the time the patient goes home.

peripheral T-cell lymphoma

One of a group of aggressive (fast-growing) non-Hodgkin�s lymphomas that begin in mature T lymphocytes (T cells that have matured in the thymus gland and gone to other lymphatic sites in the body, including lymph nodes, bone marrow, and spleen.) Also called mature T-cell lymphoma.

peripheral blood

Blood circulating throughout the body.

peripheral blood lymphocyte therapy

A treatment for Epstein-Barr virus infection or overgrowth of white blood cells (lymphocytes) after an organ or bone marrow transplant. Specific lymphocytes from a sibling donor are infused into the patient to try and reverse these conditions.

peripheral blood smear

A procedure in which a sample of blood is viewed under a microscope to count different circulating blood cells (red blood cells, white blood cells, platelets, etc.) and see whether the cells look normal.

peripheral neuropathy

A condition of the nervous system that causes numbness, tingling, burning or weakness. It usually begins in the hands or feet, and can be caused by certain anticancer drugs.

peripheral primitive neuroectodermal tumor

pPNET. A type of cancer that forms in bone or soft tissue. Also called Ewing's sarcoma.

peripheral stem cell

An immature cell found circulating in the bloodstream. New blood cells develop from peripheral stem cells.

peripheral stem cell support

A method of replacing blood-forming cells destroyed by cancer treatment. Immature blood cells (stem cells) in the circulating blood that are similar to those in the bone marrow are given to the patient after treatment. This helps the bone marrow recover and continue producing healthy blood cells. Transplantation may be autologous (an individual's own blood cells saved earlier), allogeneic (blood cells donated by someone else), or syngeneic (blood cells donated by an identical twin). Also called peripheral stem cell transplantation.

peripheral stem cell transplantation

A method of replacing blood-forming cells destroyed by cancer treatment. Immature blood cells (stem cells) in the circulating blood that are similar to those in the bone marrow are given to the patient after treatment. This helps the bone marrow recover and continue producing healthy blood cells. Transplantation may be autologous (an individual's own blood cells saved earlier), allogeneic (blood cells donated by someone else), or syngeneic (blood cells donated by an identical twin). Also called peripheral stem cell support.

peristalsis

The rippling motion of muscles in the intestine or other tubular organs characterized by the alternate contraction and relaxation of the muscles that propel the contents onward.

peritoneal

Having to do with the parietal peritoneum (the tissue that lines the abdominal wall and pelvic cavity) and visceral peritoneum (the tissue that covers most of the organs in the abdomen, including the intestines).

peritoneal cancer

Cancer of the tissue that lines the abdominal wall and covers organs in the abdomen.

peritoneal cavity

The space within the abdomen that contains the intestines, the stomach, and the liver. It is bound by thin membranes.

peritoneal infusion

A method of delivering fluids and drugs directly into the abdominal cavity through a thin tube. Also called intraperitoneal infusion.

peritoneal perfusion

A method of delivering fluids and drugs directly to tumors in the peritoneal cavity.

peritoneum

The tissue that lines the abdominal wall and covers most of the organs in the abdomen.

peritonitis

Inflammation of the peritoneum (tissue that lines the abdominal wall and covers most of the organs in the abdomen). Peritonitis can result from infection, injury, or certain diseases. Symptoms may include swelling of the abdomen, severe pain, and weight loss.

pernicious anemia

A type of anemia (low red blood cell count) caused by the body's inability to absorb vitamin B12.

perturbation

A disruption or disturbance.

pertuzumab

A monoclonal antibody that is being studied in the treatment of cancer. Monoclonal antibodies are produced in the laboratory and can locate and bind to cancer cells.

pesticide

A chemical that is used to kill insects and other pests.

petechiae

Pinpoint, unraised, round red spots under the skin caused by bleeding.

phagocyte

An immune system cell that can surround and kill microorganisms and remove dead cells. Phagocytes include macrophages.

phantom limb pain

The sensation of pain or other unpleasant feelings in the place of a missing (phantom) limb.

pharmacokinetics

The activity of drugs in the body over a period of time, including the processes by which drugs are absorbed, distributed in the body, localized in the tissues, and excreted.

pharmacopoeia

A book describing chemicals, drugs, and other substances and how they are used as medicines. It is prepared by a recognized authority.

pharynx

The hollow tube inside the neck that starts behind the nose and ends at the top of the trachea (windpipe) and esophagus (the tube that goes to the stomach). The pharynx is about 5 inches long, depending on body size. Also called the throat.

phase I detoxification

A process in which the liver uses one of two major enzyme pathways to change a toxic substance, such as an anticancer drug, into a less toxic substance that is easier for the body to excrete.

phase I trial

The first step in testing a new treatment in humans. These studies test the best way to give a new treatment (for example, by mouth, intravenous infusion, or injection) and the best dose. The dose is usually increased a little at a time in order to find the highest dose that does not cause harmful side effects. Because little is known about the possible risks and benefits of the treatments being tested, phase I trials usually include only a small number of patients who have not been helped by other treatments.

phase I/II trial

A trial to study the safety, dosage levels, and response to a new treatment.

phase II detoxification

A process in which the liver uses one of two major enzyme pathways to change a toxic substance, such as an anticancer drug, into a less toxic substance that is easier for the body to excrete. In phase II detoxification, liver cells add a substance (such as cysteine, glycine, or a sulfur molecule) to a toxic chemical or drug, to make it less harmful.

phase II trial

A study to test whether a new treatment has an anticancer effect (for example, whether it shrinks a tumor or improves blood test results) and whether it works against a certain type of cancer.

phase II/III trial

A trial to study response to a new treatment and the effectiveness of the treatment compared with the standard treatment regimen.

phase III trial

A study to compare the results of people taking a new treatment with the results of people taking the standard treatment (for example, which group has better survival rates or fewer side effects). In most cases, studies move into phase III only after a treatment seems to work in phases I and II. Phase III trials may include hundreds of people.

phase IV trial

After a treatment has been approved and is being marketed, it is studied in a phase IV trial to evaluate side effects that were not apparent in the phase III trial. Thousands of people are involved in a phase IV trial.

phenethyl isothiocyanate

PEITC. A substance that is being studied in the prevention of cancer. It is a naturally occurring compound found in some cruciferous vegetables.

phenobarbital

A drug that is used to treat seizures and as a sedative. It is being studied in the treatment of diarrhea and for its ability to increase the antitumor effect of other therapies. It belongs to the family of drugs called barbiturates.

phenoxodiol

A substance that is being studied in the treatment of cancer. It belongs to the family of drugs called signal transduction inhibitors.

phenylacetate

A substance that is being studied in the treatment of cancer.

phenylbutyrate

A substance that is being studied in the treatment of cancer. It belongs to the family of drugs called differentiating agents.

pheochromocytoma

A tumor of the adrenal gland that causes it to produce too much adrenaline. Pheochromocytomas are usually benign (noncancerous), but can cause dangerously high blood pressure and other symptoms, including pounding headaches, heart palpitations, flushing of the face, nausea, and vomiting.

pheresis

A procedure in which blood is collected, part of the blood such as platelets or white blood cells is taken out, and the rest of the blood is returned to the donor. Also called apheresis.

phlebotomy

The puncture of a vein with a needle for the purpose of drawing blood. Also called venipuncture.

phospholipid

A lipid (fat) that contains phosphorus. Phospholipids are a major part of cell membranes.

phospholipid complex

A chemical or drug that is attached to a lipid (fat) that contains phosphorus.

phosphorous

Having to do with or containing the element phosphorus.

phosphorus

A nonmetallic element that is found in the blood, muscles, nerves, bones, and teeth and is a component of adenosine triphosphate (ATP; the primary energy source for the body's cells).

phosphorus-32

A radioactive form of phosphorus used in the treatment of cancer. It is also used to help locate areas of DNA damage.

photoactivity

The effect produced when certain substances are exposed to light. In cancer treatment, some drugs become active when exposed to light and are then able to kill tumor cells.

photodynamic therapy

Treatment with drugs that become active when exposed to light. These drugs kill cancer cells.

photopheresis

A procedure in which blood is removed from the body and treated with ultraviolet light and drugs that become active when exposed to light. The blood is then returned to the body. It is being studied in the treatment of some blood and bone marrow diseases and graft-vs-host disease (GVHD). Also called extracorporeal photopheresis.

photophobia

A condition in which the eyes are more sensitive than normal to light.

photosensitizer

A drug used in photodynamic therapy. When absorbed by cancer cells and exposed to light, the drug becomes active and kills the cancer cells. Also called photosensitizing agent.

photosensitizing agent

A drug used in photodynamic therapy. When absorbed by cancer cells and exposed to light, the drug becomes active and kills the cancer cells. Also called photosensitizer.

phyllodes tumor

A type of tumor found in breast tissue. It is often large and bulky and grows quickly. It is usually benign (not cancer), but may be malignant (cancer). Also called cystosarcoma phyllodes.

physical examination

An exam of the body to check for general signs of disease.

physical therapist

A health professional who teaches exercises and physical activities that help condition muscles and restore strength and movement.

physical therapy

The use of exercises and physical activities to help condition muscles and restore strength and movement. For example, physical therapy can be used to restore arm and shoulder movement and build back strength after breast cancer surgery.

physician

Medical doctor.

physiologic

Having to do with the functions of the body. When used in the phrase "physiologic age," it refers to an age assigned by general health, as opposed to calendar age.

phytic acid

A substance found in many foods that come from plants, including corn, wheat, rice, and soybeans, and in large amounts in cereals and legumes. It is being studied in the prevention of cancer. Also called inositol hexaphosphate (IP6).

phytochemical

A substance found in plants. Some phytochemicals may reduce the risk of cancer.

phytoestrogen

An estrogen-like substance found in some plants and plant products. Phytoestrogens may have anticancer effects.

phytosterol

A plant-based compound that can compete with dietary cholesterol to be absorbed by the intestines, resulting in lower blood cholesterol levels. Phytosterols may have some effect in cancer prevention. Also called plant sterol.

pigment

A substance that gives color to tissue. Pigments are responsible for the color of skin, eyes, and hair.

pilocarpine

A drug used to increase salivation in people who have dry mouth caused by opioids or radiation therapy. Pilocarpine belongs to the family of drugs called alkaloids.

pilocytic

Made up of cells that look like fibers when viewed under a microscope.

pilot study

The initial study examining a new method or treatment.

pineal body

A tiny organ in the cerebrum that produces melatonin. Also called pineal gland or pineal organ.

pineal gland

A tiny organ in the cerebrum that produces melatonin. Also called pineal body or pineal organ.

pineal organ

A tiny organ in the cerebrum that produces melatonin. Also called pineal body or pineal gland.

pineal region tumor

A type of brain tumor that occurs in or around the pineal gland, a tiny organ near the center of the brain.

pineoblastoma

A fast growing type of brain tumor that occurs in or around the pineal gland, a tiny organ near the center of the brain.

pineocytoma

A slow growing type of brain tumor that occurs in or around the pineal gland, a tiny organ near the center of the brain.

pinkeye

A condition in which the conjunctiva (membranes lining the eyelids and covering the white part of the eye) become inflamed or infected. Also called conjunctivitis.

pioglitazone

A drug that is used to treat type 2 diabetes and is being studied in the prevention of head and neck cancer. It may be able to stop leukoplakia (a precancerous condition affecting the mouth) from developing into cancer. It belongs to the family of drugs called thiazolidinediones. Also called Actos.

piperacillin-tazobactam

A drug combination that is used to treat infection in people with cancer. Piperacillin is a synthetic penicillin; tazobactam enhances the effectiveness of piperacillin.

pirfenidone

A substance that is being studied in the prevention and treatment of scar tissue caused by radiation therapy. It belongs to the family of drugs called anti-inflammatory agents.

pituitary gland

The main endocrine gland. It produces hormones that control other glands and many body functions, especially growth.

pixantrone

A substance that is being studied in the treatment of cancer. It belongs to the family of drugs called antitumor antibiotics. Also called BBR 2778.

placebo

An inactive substance or treatment that looks the same as, and is given the same way as, an active drug or treatment being tested. The effects of the active drug or treatment are compared to the effects of the placebo.

placebo-controlled

Refers to a clinical study in which the control patients receive a placebo.

placenta

The organ that nourishes the developing fetus in the uterus.

placental blood transplantation

The transfer of blood from a placenta to an individual whose own blood production system is suppressed. Placental blood contains high levels of stem cells needed to produce new blood cells. It is being studied in the treatment of cancer and severe blood disorders such as aplastic anemia. Also called umbilical cord blood transplant.

plant sterol

A plant-based compound that can compete with dietary cholesterol to be absorbed by the intestines, resulting in lower blood cholesterol levels. Plant sterols may have some effect in cancer prevention. Also called phytosterol.

plaque

In medicine, a small, abnormal patch of tissue on a body part or an organ. Plaques may also be a build-up of substances from a fluid, such as cholesterol in the blood vessels.

plasma

The clear, yellowish, fluid part of the blood that carries the blood cells. The proteins that form blood clots are in plasma.

plasma cell

A type of white blood cell that produces antibodies.

plasma cell myeloma

A type of cancer that begins in plasma cells (white blood cells that produce antibodies). Also called multiple myeloma, Kahler's disease, or myelomatosis.

plasma cell tumor

A tumor that begins in plasma cells (white blood cells that produce antibodies). Multiple myeloma, monoclonal gammopathy of undetermined significance (MGUS), and plasmacytoma are types of plasma cell tumors.

plasma membrane

The outer membrane of a cell.

plasmacytic

Having to do with plasma cells (a type of white blood cells).

plasmacytoma

A type of cancer that begins in plasma cells (white blood cells that produce antibodies). A plasmacytoma may turn into multiple myeloma.

plasmapheresis

The process of separating certain cells from the plasma in the blood by a machine; only the cells are returned to the person. Plasmapheresis can be used to remove excess antibodies from the blood.

plastic surgeon

A surgeon who specializes in reducing scarring or disfigurement that may occur as a result of accidents, birth defects, or treatment for diseases.

plastic surgery

An operation that restores or improves the appearance of body structures.

platelet

A type of blood cell that helps prevent bleeding by causing blood clots to form. Also called a thrombocyte.

platinum

A metal that is an important component of some anticancer drugs, such as cisplatin and carboplatin.

pleomorphic

Occurring in various distinct forms. In terms of cells, having variation in the size and shape of cells or their nuclei.

pleura

A thin layer of tissue covering the lungs and lining the interior wall of the chest cavity. It protects and cushions the lungs. This tissue secretes a small amount of fluid that acts as a lubricant, allowing the lungs to move smoothly in the chest cavity while breathing.

pleural cavity

The space enclosed by the pleura, which is a thin layer of tissue that covers the lungs and lines the interior wall of the chest cavity.

pleural effusion

An abnormal collection of fluid between the thin layers of tissue (pleura) lining the lung and the wall of the chest cavity.

pleurodesis

A medical procedure that uses chemicals or drugs to cause inflammation and adhesion between the layers of the pleura (the tissue that covers the lungs and lines the interior wall of the chest cavity). This prevents the buildup of fluid in the pleural cavity. It is used as a treatment for severe pleural effusion.

plexiform neurofibroma

A nerve that has become thick and misshapen due to the abnormal growth of cells and tissues that cover the nerve.

plexopathy

A disorder affecting a network of nerves, blood vessels, or lymph vessels.

ploidy

The number of sets of chromosomes in a cell or an organism. For example, haploid means one set and diploid means two sets.

pluripotent

Able to mature or develop in any of several ways.

pluripotent stem cell

A cell that is able to develop into several different types of cells or tissues in the body.

pneumatic larynx

A device that is used to help a person talk after a laryngectomy. It uses air to produce a humming sound, which is converted to speech by movement of the lips, tongue, or glottis.

pneumonectomy

An operation to remove an entire lung.

pneumonia

An inflammatory infection that occurs in the lung.

polifeprosan 20 carmustine implant

A biodegradable wafer that is used to deliver the anticancer drug carmustine directly into a brain tumor site after the tumor has been removed by surgery. Also called Gliadel Wafer.

poly-ICLC

A substance that is being studied in the treatment of cancer and for its ability to stimulate the immune system. It is made in the laboratory by combining the nucleic acid RNA with the chemicals poly-L-lysine and carboxymethyl cellulose.

polycythemia vera

A disease in which there are too many red blood cells in the bone marrow and blood, causing the blood to thicken. The number of white blood cells and platelets may also increase. The extra blood cells may collect in the spleen and cause it to become enlarged. They may also cause bleeding problems and make clots form in blood vessels.

polyethylene glycosylated recombinant human megakaryocyte growth and development factor

PEG-rhMGDF. A form of megakaryocyte growth and development factor (MGDF) that is made in the laboratory. MGDF comes from the protein thrombopoietin, which is normally made in the body to help make platelets. Polyethylene glycosylated recombinant human megakaryocyte growth and development factor is being studied as a way to increase the number of platelets in patients receiving chemotherapy. Also called PEG-MGDF.

polyethylene glycosylated recombinant human megakaryocytegrowth and development factor

PEG-rhMGDF. A form of megakaryocyte growth and development factor (MGDF) that is made in the laboratory. MGDF comes from the protein thrombopoietin, which is normally made in the body to help make platelets. Polyethylene glycosylated recombinant human megakaryocyte growth and development factor is being studied as a way to increase the number of platelets in patients receiving chemotherapy. Also called PEG-MGDF.

polyglutamate camptothecin

A form of the anticancer drug camptothecin that may have fewer side effects and work better than camptothecin. It is being studied in the treatment of cancer. It belongs to the family of drugs called DNA topoisomerase inhibitors. Also called CT-2106.

polyglutamate paclitaxel

A protein that can be linked to a chemotherapy drug to deliver the drug directly to the tumor with fewer side effects. It is being studied as a treatment for cancer. Also called CT-2103.

polymerase chain reaction

PCR. A laboratory method used to make many copies of a specific DNA sequence.

polymorphism

A common variation or mutation in DNA.

polyneuritis

Inflammation of several peripheral nerves at the same time.

polyp

A growth that protrudes from a mucous membrane.

polypectomy

Surgery to remove a polyp.

polyphenol

A substance that is found in many plants and gives some flowers, fruits, and vegetables their color. Polyphenols have antioxidant activity.

polyposis

The development of numerous polyps (growths that protrude from a mucous membrane).

polysaccharide

A type of carbohydrate. It contains sugar molecules that are linked together chemically.

pons

Part of the central nervous system, located at the base of the brain, between the medulla oblongata and the midbrain. It is part of the brainstem.

pontine

Having to do with the pons (part of the central nervous system, located at the base of the brain, between the medulla oblongata and the midbrain).

porfimer sodium

A drug used to treat some types of cancer. When absorbed by cancer cells and exposed to light, porfimer sodium becomes active and kills the cancer cells. It belongs to the family of drugs called photodynamic therapy agents. Also called Photofrin.

porfiromycin

A substance that is being studied in the treatment of cancer. It belongs to the family of drugs called anticancer antibiotics.

port

An implanted device through which blood may be withdrawn and drugs may be infused without repeated needle sticks. Also called a port-a-cath.

port-a-cath

An implanted device through which blood may be withdrawn and drugs may be infused without repeated needle sticks. Also called a port.

portal hypertension

High blood pressure in the vein that carries blood to the liver from the stomach, small and large intestines, spleen, pancreas, and gallbladder. It is usually caused by a block in the blood flow through the liver due to cirrhosis (scarring) of the liver.

portal vein

A blood vessel that carries blood to the liver from the stomach, small and large intestines, spleen, pancreas, and gallbladder. Also called hepatic portal vein.

positive axillary lymph node

A lymph node in the area of the armpit (axilla) to which cancer has spread. This spread is determined by surgically removing some of the lymph nodes and examining them under a microscope to see whether cancer cells are present.

positive test result

A test result that reveals the presence of a specific disease or condition for which the test is being done.

positron emission tomography scan

PET scan. A procedure in which a small amount of radioactive glucose (sugar) is injected into a vein, and a scanner is used to make detailed, computerized pictures of areas inside the body where the glucose is used. Because cancer cells often use more glucose than normal cells, the pictures can be used to find cancer cells in the body.

postmenopausal

Having to do with the time after menopause. Menopause ("change of life") is the time in a woman's life when menstrual periods stop permanently.

postmortem

After death. Often used to describe an autopsy.

postoperative

After surgery.

postprandial

After a meal.

postremission therapy

Anticancer drugs given to kill cancer cells that survive after remission induction therapy.

potassium

A metallic element that is important in body functions such as regulation of blood pressure and of water content in cells, transmission of nerve impulses, digestion, muscle contraction, and heartbeat.

potassium hydroxide

A toxic and highly corrosive chemical used to make soap, in bleaching, and as a paint remover. It is used in small amounts as a food additive and in the preparation of some drugs.

potentiation

In medicine, the effect of increasing the potency or effectiveness of a drug or other treatment.

pravastatin

A drug that lowers the amount of cholesterol in the blood. It may also make tumor cells more sensitive to anticancer drugs, and is being studied in the treatment of cancer. It belongs to the families of drugs called HMG-CoA reductase inhibitors (statins) and chemosensitizers. Also called Pravachol.

precancerous

A term used to describe a condition that may (or is likely to) become cancer. Also called premalignant.

precancerous dermatitis

A skin disease marked by scaly or thickened patches on the skin, and often caused by prolonged exposure to arsenic. The patches often occur on sunexposed areas of the skin and in older white men. These patches may become malignant (cancerous). Also called Bowen's disease or precancerous dermatosis.

precancerous dermatosis

A skin disease marked by scaly or thickened patches on the skin, and often caused by prolonged exposure to arsenic. The patches often occur on sunexposed areas of the skin and in older white men. These patches may become malignant (cancerous). Also called Bowen's disease or precancerous dermatitis.

precancerous polyps

Growths that protrude from a mucous membrane. Precancerous polyps may (or are likely to) become cancer.

preclinical study

Research using animals to find out if a drug, procedure, or treatment is likely to be useful. Preclinical studies take place before any testing in humans is done.

predictive factor

A situation or condition that may increase a person's risk of developing a certain disease or disorder.

prednisolone

A drug that is used to treat blood cell cancers (leukemias) and lymph system cancers (lymphomas). It belongs to the family of drugs called synthetic corticosteroids.

prednisone

A drug that is used to treat several types of cancer and other disorders. Prednisone also inhibits the body's immune response. It belongs to the family of drugs called steroids.

preleukemia

A disease in which the bone marrow does not function normally. Also called myelodysplastic syndrome or smoldering leukemia.

premalignant

A term used to describe a condition that may (or is likely to) become cancer. Also called precancerous.

premature ovarian failure

A condition in which the ovaries stop working before age 40. Symptoms include hot flashes, mood swings, night sweats, vaginal dryness, and infertility. Some cancer treatments, such as chemotherapy and radiation therapy, can cause premature ovarian failure. Ovarian failure may be temporary or permanent and may be treated with hormone replacement therapy. Also called primary ovarian insufficiency.

premenopausal

Having to do with the time before menopause. Menopause ("change of life") is the time of life when a woman's menstrual periods stop permanently.

premycotic phase

A phase of mycosis fungoides in which a patient has areas of red, scaly, itchy skin on areas of the body that are usually not exposed to sun. This is early-phase mycosis fungoides, but it is hard to diagnose the rash as mycosis fungoides during this phase. The premycotic phase may last from months to decades.

prescription

A doctor's order for medicine or another intervention.

pretracheal space

The area in front of the trachea (windpipe).

prevascular space

The area in the front part of the chest between the lungs. Also called anterior mediastinum.

prevention

In medicine, action taken to decrease the chance of getting a disease. For example, cancer prevention includes avoiding risk factors (such as smoking, obesity, lack of exercise, and radiation exposure) and increasing protective factors (such as getting regular physical activity, staying at a healthy weight, and having a healthy diet).

preventive

Used to prevent disease.

preventive mastectomy

Surgery to reduce the risk of developing breast cancer by removing one or both breasts before disease develops. Also called prophylactic mastectomy.

primary care doctor

A doctor who manages a person's health care over time. A primary care doctor is able to give a wide range of care, including prevention and treatment, can discuss cancer treatment choices, and can refer a patient to a specialist.

primary central nervous system lymphoma

Cancer that arises in the lymphoid tissue found in the central nervous system (CNS). The CNS includes the brain and spinal cord.

primary endpoint

The main result that is measured at the end of a study to see if a given treatment worked (e.g., the number of deaths or the difference in survival between the treatment group and the control group). What the primary endpoint will be is decided before the study begins.

primary myelofibrosis

A progressive, chronic disease in which the bone marrow is replaced by fibrous tissue and blood is made in organs such as the liver and the spleen, instead of in the bone marrow. This disease is marked by an enlarged spleen and progressive anemia. Also called chronic idiopathic myelofibrosis, agnogenic myeloid metaplasia, myelosclerosis with myeloid metaplasia, and idiopathic myelofibrosis.

primary ovarian insufficiency

A condition in which the ovaries stop working before age 40. Symptoms include hot flashes, mood swings, night sweats, vaginal dryness, and infertility. Some cancer treatments, such as chemotherapy and radiation therapy, can cause premature ovarian failure. Ovarian failure may be temporary or permanent and may be treated with hormone replacement therapy. Also called premature ovarian failure.

primary tumor

The original tumor.

primitive neuroectodermal tumor

PNET. One of a group of cancers that develop from the same type of early cells, and share certain biochemical and genetic features. Some PNETs develop in the brain and central nervous system (CNS-PNET), and others develop in sites outside of the brain such as the limbs, pelvis, and chest wall (peripheral PNET).

prinomastat

A substance that is being studied in the treatment of cancer. It is a matrix metalloproteinase inhibitor and belongs to the family of drugs called angiogenesis inhibitors. Also called AG3340.

pro-oxidant

A substance that can produce oxygen byproducts of metabolism that can cause damage to cells.

probenecid

A drug that is used to treat gout and is used together with some antibiotics to make them work better. It is being studied in the treatment of cancer. It belongs to the family of drugs called antibiotic therapy adjuncts.

procarbazine

A drug that is used to treat cancer. It belongs to the family of drugs called alkylating agents.

prochlorperazine

A drug used to prevent or reduce nausea and vomiting. It belongs to the family of drugs called antiemetics.

proctoscopy

An examination of the rectum using a thin, lighted tube called a proctoscope.

proctosigmoidoscopy

An examination of the lower colon using a thin, lighted tube, called a sigmoidoscope, inserted into the rectum. Samples of tissues may be collected for examination under a microscope. Also called sigmoidoscopy.

progeny

Offspring; the product of reproduction or replication.

progesterone

A female hormone.

progesterone receptor

PR. A protein found inside the cells of the female reproductive tissue, some other types of tissue, and some cancer cells. The hormone progesterone will bind to the receptors inside the cells and may cause the cells to grow.

progesterone receptor negative

PR-. Breast cancer cells that do not have a protein (receptor molecule) to which progesterone will attach. Breast cancer cells that are PR- do not need the hormone progesterone to grow and usually do not respond to hormonal therapy.

progesterone receptor positive

PR+. Breast cancer cells that have a protein (receptor molecule) to which progesterone will attach. Breast cancer cells that are PR+ need the hormone progesterone to grow and will usually respond to hormonal therapy.

progesterone receptor test

A lab test to determine if breast cancer cells have progesterone receptors. If the cells have progesterone receptors, they may depend on progesterone for growth. This information can influence how the breast cancer is treated.

progestin

Any natural or laboratory-made substance that has some or all of the biologic effects of progesterone, a female hormone.

prognosis

The likely outcome or course of a disease; the chance of recovery or recurrence.

prognostic factor

A situation or condition, or a characteristic of a patient, that can be used to estimate the chance of recovery from a disease or the chance of the disease recurring (coming back).

programmed cell death

A type of cell death in which a series of molecular steps in a cell leads to its death. This is the body's normal way of getting rid of unneeded or abnormal cells. The process of programmed cell death may be blocked in cancer cells. Also called apoptosis.

progression

Increase in the size of a tumor or spread of cancer in the body.

progression-free survival

One type of measurement that can be used in a clinical study or trial to help determine whether a new treatment is effective. It refers to the probability that a patient will remain alive, without the disease getting worse.

progressive disease

Cancer that is growing, spreading, or getting worse.

proliferating

Multiplying or increasing in number. In biology, cell proliferation occurs by a process known as cell division.

proliferative index

A measure of the number of cells in a tumor that are dividing (proliferating). May be used with the S-phase fraction to give a more complete understanding of how fast a tumor is growing.

prolymphocytic leukemia

PLL. A type of chronic lymphocytic leukemia (CLL), in which too many immature white blood cells (prolymphocytes) are found in the blood and bone marrow. PLL usually progresses more rapidly than classic CLL.

promegapoietin

A drug given during chemotherapy to increase blood cell regeneration. Promegapoietin is a colony-stimulating factor that stimulates the production of blood cells, especially platelets. It is a cytokine and belongs to the family of drugs called hematopoietic (blood-forming) agents.

promyelocytic leukemia

A type of acute myeloid leukemia, a quickly progressing disease in which too many immature blood-forming cells are found in the blood and bone marrow.

prophylactic

In medicine, something that prevents or protects.

prophylactic cranial irradiation

Radiation therapy to the head to reduce the risk that cancer will spread to the brain.

prophylactic mastectomy

Surgery to reduce the risk of developing breast cancer by removing one or both breasts before disease develops. Also called preventive mastectomy.

prophylactic oophorectomy

Surgery intended to reduce the risk of ovarian cancer by removing the ovaries before disease develops.

prophylactic surgery

Surgery to remove an organ or gland that shows no signs of cancer, in an attempt to prevent development of cancer of that organ or gland. Prophylactic surgery is sometimes chosen by people who know they are at high risk for developing cancer.

prophylaxis

An attempt to prevent disease.

prospective

In medicine, a study or clinical trial in which participants are identified and then followed forward in time.

prospective cohort study

A research study that follows over time groups of individuals who are alike in many ways but differ by a certain characteristic (for example, female nurses who smoke and those who do not smoke) and compares them for a particular outcome (such as lung cancer).

prostate

A gland in the male reproductive system. The prostate surrounds the part of the urethra (the tube that empties the bladder) just below the bladder, and produces a fluid that forms part of the semen.

prostate-specific antigen

PSA. A substance produced by the prostate that may be found in an increased amount in the blood of men who have prostate cancer, benign prostatic hyperplasia, or infection or inflammation of the prostate.

prostate-specific antigen test

A blood test that measures the level of prostate-specific antigen (PSA), a substance produced by the prostate and some other tissues in the body. Increased levels of PSA may be a sign of prostate cancer.

prostatectomy

An operation to remove part or all of the prostate. Radical (or total) prostatectomy is the removal of the entire prostate and some of the tissue around it.

prostatic acid phosphatase

PAP. An enzyme produced by the prostate. It may be found in increased amounts in men who have prostate cancer.

prostatic intraepithelial neoplasia

PIN. Noncancerous growth of the cells lining the internal and external surfaces of the prostate gland. Having high-grade PIN may increase the risk of developing prostate cancer.

prostatitis

Inflammation of the prostate gland.

prosthesis

A device, such as an artificial leg, that replaces a part of the body.

prosthodontist

A dentist who specializes in replacing missing teeth or other structures of the mouth to restore an individual's appearance, comfort, or health.

protease inhibitor

A compound that interferes with the ability of certain enzymes to break down proteins. Some protease inhibitors can keep a virus from making copies of itself (for example, AIDS virus protease inhibitors), and some can prevent cancer cells from spreading.

proteasome inhibitor

A drug that blocks the action of proteasomes. A proteasome is a large protein complex that helps destroy other cellular proteins when they are no longer needed. Proteasome inhibitors are being studied in the treatment of cancer.

protective factor

Something that may decrease the chance of getting a certain disease. Some examples of protective factors for cancer are getting regular physical activity, staying at a healthy weight, and having a healthy diet.

protein

A molecule made up of amino acids that are needed for the body to function properly. Proteins are the basis of body structures such as skin and hair and of substances such as enzymes, cytokines, and antibodies.

protein kinase C

PKC. An enzyme found throughout the body's tissues and organs. Several forms of PKC are involved in many cellular functions. PKC is being studied in the treatment of cancer.

proteoglycan

A molecule that contains both protein and glycosaminoglycans, which are a type of polysaccharide. Proteoglycans are found in cartilage and other connective tissues.

proteomic profile

An evaluation of proteins in a sample of blood. This may help detect early cancer or cancer recurrence, or help predict response to treatment.

proteomics

The study of the structure and function of proteins, including the way they work and interact with each other inside cells.

protocol

An action plan for a clinical trial. The plan states what the study will do, how, and why. It explains how many people will be in it, who is eligible to participate, what study agents or other interventions they will be given, what tests they will receive and how often, and what information will be gathered.

proton

A small, positively charged particle of matter found in the atoms of all elements. Streams of protons generated by special equipment can be used for radiation treatment.

proton beam radiation therapy

A type of radiation therapy that uses protons generated by a special machine. A proton is a type of high-energy radiation that is different from an x-ray.

proton magnetic resonance spectroscopic imaging

A noninvasive imaging method that provides information about cellular activity (metabolic information). It is used along with magnetic resonance imaging (MRI) which provides information about the shape and size of the tumor (spacial information). Also called magnetic resonance spectroscopic imaging and 1H-nuclear magnetic resonance spectroscopic imaging.

protozoal

Having to do with the simplest organisms in the animal kingdom. Protozoa are single-cell organisms, such as ameba, and are different from bacteria, which are not members of the animal kingdom. Some protozoa can be seen without a microscope.

proximal

In medicine, refers to a part of the body that is closer to the center of the body than another part. For example, the knee is proximal to the toes. The opposite is distal.

psammoma body

A structure found in some benign (noncancerous) or malignant (cancerous) tumor cells. Psammoma bodies look like hardened concentric rings when viewed under a microscope. They can be a sign of chronic inflammation.

pseudomyxoma peritonei

A build-up of mucus in the peritoneal cavity. The mucus may come from ruptured ovarian cysts, the appendix, or from other abdominal tissues, and mucus-secreting cells may attach to the peritoneal lining and continue to secrete mucus.

psoralen

A substance from plants that is sensitive to light (or can be activated by light). Psoralens are used together with UV light to treat psoriasis, vitiligo, and skin nodules of cutaneous T-cell lymphoma. They are also being studied in the treatment of graft-versus-host disease. They belong to the family of drugs called furocoumarins. An example of a psoralen is methoxsalen.

psoralen and ultraviolet A therapy

PUVA therapy. A type of photodynamic therapy used to treat skin conditions such as psoriasis, vitiligo, and skin nodules of cutaneous T-cell lymphoma. The patient receives psoralen (a drug that becomes active when it is exposed to light) by mouth or applied to the skin, followed by ultraviolet A radiation. PUVA therapy may increase the risk of getting skin cancer.

psoriasis

A chronic disease of the skin marked by red patches covered with white scales.

psychologist

A specialist who can talk with patients and their families about emotional and personal matters, and can help them make decisions.

ptosis

Drooping of the upper eyelid.

puberty

The time of life when a child experiences physical and hormonal changes, develops secondary sexual characteristics, and becomes able to have children. Secondary sexual characteristics include growth of pubic, armpit, and leg hair; breast enlargement; and increased hip width in girls. In boys, they include growth of pubic, face, chest and armpit hair; voice changes; penis and testicle growth, and increased shoulder width.

pulmonary

Having to do with the lungs.

pulmonary rehabilitation education

Education about behavior and lifestyle changes to help patients with chronic lung disease decrease breathing problems, return to daily activities, and improve quality of life. Education may include instruction about breathing exercises, nutrition, use of medicines, and ways for the patient to reduce stress and save energy.

pulmonary sulcus tumor

A type of lung cancer that begins in the upper part of a lung and spreads to nearby tissues such as the ribs and vertebrae. Most pulmonary sulcus tumors are non-small cell cancers. Also called Pancoast tumor.

pump

A device that is used to give a controlled amount of a liquid at a specific rate. For example, pumps are used to give drugs (such as chemotherapy or pain medicine) or nutrients

punch biopsy

Removal of a small disk-shaped sample of tissue using a sharp, hollow device. The tissue is then examined under a microscope.

pyrazine diazohydroxide

A substance that is being studied in the treatment of cancer.

pyrazoloacridine

A substance that is being studied in the treatment of cancer. It belongs to the family of drugs called acridines.

pyroxamide

A substance that is being studied in the treatment of cancer. It belongs to the family of drugs called histone deacetylase inhibitors.