Testing for Inherited Gene Mutations in Prostate Cancer Equally Important

More than 12 percent of men with prostate cancer tested positive for hereditary mutations of cancer-causing genes, according to study results presented at the 2018 Genitourinary Cancers Symposium.

In turn, these findings support the need for genetic testing in men with prostate cancer, which ultimately may aid in medical management and decision making that could reduce overall cancer risk.

“There is a high prevalence of pathogenic variants in genes that confer hereditary cancer risk among men with metastatic prostate cancer,” the researchers wrote. “Currently, prostate cancer is not regarded as an indication for genetic testing.”

Therefore, researchers from Virginia Cancer Specialists and Myriad Genetic Laboratories tested men with a personal history of prostate cancer using the myRisk® Hereditary Cancer test, a multi-gene hereditary cancer panel.

Over a four-year period, 1,240 men with a personal history of prostate cancer were tested with the hereditary cancer panel, including 794 men who had a history of only prostate cancer and 446 men who had a history of prostate cancer and at least one additional cancer. The most common additional cancer was colon (33.6 percent) and breast cancer (31.8 percent).

Overall, 12.1 percent of the 1,162 men included in the analysis were found to have carried one or more pathogenic variant, which was significantly higher among men with a personal history of cancer and another cancer (14.7 percent) compared with men who only had prostate cancer before (10.6 percent).

In particular, the prevalence of the BRCA2 mutation appeared to be higher in men with only prostate cancer, and mismatch repair mutations were higher in men with additional cancer history, of which most had cancers associated with Lynch syndrome.

“As one of the largest studies of hereditary cancer risk assessment ever conducted in prostate cancer, our 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,” Johnathan Lancaster, M.D., Ph.D., chief medical officer of Myriad Genetics, said in a press release. “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.”

In addition, these results may have clinical implications on how men are treated moving forward, as well as for family members of these patients.

“We believe hereditary cancer testing can help inform treatment decisions for these men, including whether to pursue active surveillance, increased screening for secondary cancers and potentially for treatment selection with PARP inhibitors or other medicines in the future,” said Lancaster. “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.”