A St. Jude Children’s Research Hospital study suggests that all childhood cancer survivors should consider genetic counseling to find out who is mostly likely to benefit from genetic testing.
The study involved whole genome sequencing of 3,006 St. Jude childhood cancer survivors. Almost 6% of those survivors had germline, likely inherited, mutations in one of 60 genes that can lead to cancer. The number of mutations in this group was about 10-fold greater than among people with no childhood cancer history. Germline mutations are found in the DNA of every cell.
The research identified survivors who should be given priority for genetic testing. That group includes those who developed second cancers, but did not have radiation therapy as pediatric cancer patients. Survivors who had radiation and later got breast cancer or sarcoma at the treatment site should also be tested.
“At medical centers without a cancer predisposition program or ready access to genetic counselors, priority should be given to the high-risk survivors identified in this study,” said Kim Nichols, MD. She directs the St. Jude Division of Cancer Predisposition.
Genetic counselors work with patients and families to decide who should get genetic testing. Counselors also clarify the risks and benefits of testing. St. Jude offers this service to every new patient with cancer. The counseling is also offered to St. Jude cancer survivors.
Clinicians used to offer screening for inherited mutations primarily to survivors with family histories of cancer. But thousands more childhood cancer survivors could benefit from counseling and testing, said Jinghui Zhang, PhD. She chairs the St. Jude Department of Computational Biology.
The study marks the first time whole genome sequencing has been used in a large group of childhood cancer survivors to study how genes affect lifetime cancer risk. Those with mutations were more likely than other survivors to develop additional cancers. Survivors who had undergone radiation therapy and had high-risk mutations were almost 14 times more likely to develop breast cancer than survivors without such mutations. The entire genomic data is shared with the global research community via the St. Jude Cloud.
The sequencing was done with samples from survivors enrolled in the St. Jude Lifetime Cohort study (St. Jude LIFE). St. Jude LIFE began more than 10 years ago. Its goal is to improve life for childhood cancer survivors. Participants return to campus for several days of medical exams and assessments.