by Dr. C.H. Weaver M.D. updated 2/2020
Myriad Genetics, a leader in molecular diagnostics and personalized medicine, announced today that results from a large 1,162 patient study will be featured during the poster presentation at the 2018 Genitourinary Cancer Symposium in San Francisco, Calif. The key finding is that more than 12 percent of men with prostate cancer had an inherited (i.e. hereditary) mutation in a cancer-causing gene.
“As one of the largest studies of hereditary cancer risk assessment ever conducted in prostate cancer, the myRisk Hereditary Cancer test demonstrated that roughly the same percentage of men with prostate cancer carry hereditary cancer-causing mutations as do women with breast cancer,” said Johnathan Lancaster, M.D., Ph.D., chief medical officer, Myriad Genetics. “These compelling findings provide a strong reason for expanding the use of genetic testing in men diagnosed with prostate cancer consistent with existing professional medical guidelines.”
The key data are summarized below:
The study objective was to evaluate genetic testing using the 28-gene myRisk Hereditary Cancer test in 1,162 men with a personal history of prostate cancer. Of these, 64 percent had a history of prostate cancer, while 36 percent had a history of prostate cancer and at least one additional cancer. The results showed that 12.1 percent of men with prostate cancer were positive for one or more hereditary cancer mutations in the genes tested. Additionally, the positive rate was significantly higher among men with prostate cancer plus one other cancer (14.7 percent). The inherited mutations were found in genes with a well-known prostate cancer risk (i.e., BRCA2) as well as genes historically associated with other cancer types including breast and colon. These findings suggest that hereditary cancer testing in men with prostate cancer may aid in medical management decision making to reduce overall cancer risk.
Hereditary cancer testing can help inform treatment decisions for men with prostate cancer, including whether to pursue active surveillance, increased screening for secondary cancers and potentially for treatment selection with PARP inhibitors or other precision medicines in the future. Additionally, once men know they carry an inherited mutation, they can encourage their family members to get tested to learn if they’re at increased risk for cancer and potentially help them prevent future cancers.
Germline Testing for Prostate Cancer Active Surveillance
Based on these and other studies physicians have begun to propose that germline testing be performed for all patients at the time of prostate cancer diagnosis, even those with low-risk disease.
Overall 60% of men who report no risk factors like family history of prostate cancer will have a genetic mutation. Many physicians now believe universal testing should be recommended for all men diagnosed with cancer of any grade or stage. Genetic testing is inexpensive and can identify germline mutations associated with prostate cancer risk and aggressiveness including BRCA2, ATM and MSH2 mutations.
Individuals at high genetic risk for prostate cancer should be followed more carefully based on the interim results from the IMPACT trial (Identification of Men with a genetic predisposition to ProstAte Cancer) which demonstrated that targeted screening in men at higher genetic risk with mutated BRCA2 genes can identify more men with higher-grade disease.
Individuals at higher genetic risk with a BRCA2 mutation have are more likely to have higher grade tumors and metastatic more lethal cancers. They should discuss whether they might benefit from more active surveillance (more frequent biopsies) with their managing physician.
Importantly an American Urologic Association position states that: “Patients with localized prostate cancer who are at highest risk for developing metastatic castration-resistant prostate cancer, may have a higher incidence of germline DNA repair mutations than expected from published reports. The presence of germline DNA repair gene mutations has important implications for the prostate cancer patient in terms of general cancer screening and possible future prostate cancer treatment decisions. Additionally the presence of germline DNA repair mutations is of utmost relevance to the patient’s first-degree family members due to increased cancer risk and screening implications.”
About Prostate Cancer
One in nine American men will have prostate cancer during his lifetime. Prostate cancer is the second leading cause of cancer death among American men and is the most commonly diagnosed. Currently, there are nearly 2.9 million American men living with the disease and every 18 minutes another American man dies from prostate cancer.
About Myriad myRisk® Hereditary Cancer
The Myriad myRisk Hereditary Cancer test uses an extensive number of sophisticated technologies and proprietary algorithms to evaluate 28 clinically significant genes associated with eight hereditary cancer sites including: breast, colon, ovarian, endometrial, pancreatic, prostate and gastric cancers and melanoma. Men with prostate cancer can take the Hereditary Cancer Quiz to find out if they might be at risk for an inherited mutation and qualify for myRisk Hereditary Cancer test.
- Robert Reid, M.D., Inherited Germline Mutations in Men with Prostate Cancer. Poster Board E4; 2018 Genitourinary Cancer Symposium; Abstract 357.
- Page EC, Bancroft EK, Brook MN, et al. Interim results from the IMPACT study: Evidence for prostate-specific antigen screening in BRCA2 mutation carriers [published online September 16, 2019]. Eur Urol. doi:10.1016/j.eururo.2019.08.019