Prostate cancer is one of the most heritable forms of cancer. Hereditary mutations in “DNA repair” genes – BRCA1, BRCA2, and others – which are best known for their association with breast and ovarian cancer predisposition, are now known to be associated with advanced prostate cancer. In fact, ~12% of men with metastatic prostate cancer carry hereditary mutations in DNA repair genes that may have led to the development of their cancer, according to a recent study by the Prostate Cancer Foundation (PCF) International Dream Team.

Heather Cheng, MD, PhD

Heather Cheng, MD, PhD

These findings have important implications for patients’ treatment options and for their families. First, tumors with mutations in DNA repair genes such as BRCA1/2 may be sensitive to treatment with PARP-inhibitors (e.g. olaparib, niraparib, rucaparib) and platinum chemotherapies, which are becoming increasingly available in clinical trials. Patients who discover they are mutation carriers should talk to their doctors about whether to consider these treatment options. Second, carrying a mutation in one of these genes may increase the risk of developing prostate cancer, breast cancer, ovarian cancer, and other cancers. Family members of patients with inherited DNA repair gene mutations may also have inherited these mutations and should consider genetic counseling to determine their own risk and recourse for these cancers. Because of these implications, PCF Dream Team investigators have recommended that all men with metastatic prostate cancer be offered genetic counseling to determine if they carry hereditary mutations in DNA repair genes.

“The recent discovery of a much higher prevalence of inherited cancer risk genes in men with advanced prostate cancer than previously thought — approximately one in ten — is undoubtedly exciting,” said PCF Young Investigator Dr. Heather Cheng, a medical oncologist at the Seattle Cancer Care Alliance, Assistant Member in the Clinical Research Division at Fred Hutchinson Cancer Research Center and Assistant Professor of Medical Oncology at the University of Washington, who took part in the study. “However, there are major barriers to optimal incorporation of the new findings to clinical care.   Prostate cancer clinicians are largely unfamiliar with cancer genetics and the genetics community has limited familiarity with prostate cancer. Add to this the shortage of genetic counselors, challenges with insurance coverage for genetic testing, and the misconception that many of these genes are relevant only to ‘womens’ cancers.’”

To help surmount these barriers, Dr. Cheng recently launched the country’s first prostate cancer genetics clinic at The Seattle Cancer Care Alliance to provide patients who may potentially carry these hereditary mutations with the optimal education and genetic counselling services needed to determine whether they are mutation carriers, access the latest research and innovations, and make the most informed choices for themselves and their families. The Prostate Cancer Genetics Clinic will provide prostate cancer patients with a two-part consultative service. First, patients will meet with Dr. Cheng to discuss genetics, treatment implications for mutation carriers, and recommendations for next steps for the patient and his family. Next, the patient will meet with a genetic counselor to discuss risk assessment, pre- and post-test counseling, navigation of insurance coverage for testing, and how to talk about findings with family members.

For more information on prostate cancer genetics, research opportunities including clinical trials and family studies, please call 206-288-7379 or email prostategenetics@seattlecca.org. To refer a patient to the Prostate Cancer Genetics Clinic, please call 206-288-8300.

Dr. Andrea Miyahira has a PhD in cancer immunology, and is Manager of Scientific Programs at the Prostate Cancer Foundation.