Study: Metastatic prostate cancer patients could benefit from genetic testing
Men with metastatic prostate cancer have a surprisingly high rate of inherited mutations in DNA-repair genes, suggesting that all men with such advanced prostate cancer should be considered for genetic testing, a new study concludes.
Men with metastatic prostate cancer have a surprisingly high rate of inherited mutations in DNA-repair genes, suggesting that all men with such advanced prostate cancer should be considered for genetic testing, a new study concludes.
Genetic testing is not recommended for men with cancer confined to the prostate - or men whose cancer later spreads - because studies have found less than 5 percent have defective DNA-repair genes.
But the prevalence of such defects among men who are initially diagnosed with metastatic prostate cancer has been unclear, according to the new study, published Wednesday in the New England Journal of Medicine by researchers from six leading cancer centers in the United States and Britain.
The researchers conducted genetic testing on 692 men with metastatic prostate cancer and found that 82 of them - almost 12 percent - had mutations in genes that normally help suppress cancer by repairing cellular DNA damage. Among those 82 men, the most commonly mutated gene was BRCA2, which is known to increase prostate cancer risk in men, as well as breast and ovarian cancer risk in women. The researchers also found cancer-promoting mutations in 15 other, less studied DNA-repair genes.
For women, being diagnosed with breast cancer at a young age or having a strong family history of breast and ovarian cancer increases the chance of having a BRCA1 or BRCA2 gene mutation, so such women are candidates for genetic testing. In contrast, the new study found no link between DNA-repair mutations in the men and their age at diagnosis or family cancer history.
"These findings potentially change clinical practice because we now show that testing for these DNA repair genes should be offered to all men with advanced prostate cancer," said study co-author Kenneth Offit, a cancer geneticist and oncologist at Memorial Sloan Kettering Cancer Center.
Identifying men with inherited gene defects is important for guiding their treatment and for counseling family members about whether to undergo genetic testing, the researchers wrote. They noted that recent research has shown that targeted cancer drugs called PARP inhibitors and platinum-based chemotherapy recently work well in metastatic prostate cancer patients with DNA-repair defects.
"We feel doing this testing for men with metastatic prostate cancer is appropriate because other people in the family may be affected by this genetic information," said co-author Michael F. Walsh, a geneticist and pediatric oncologist at Memorial Sloan.
The other co-authors were from Fred Hutchinson Cancer Research Center, Dana-Farber Cancer Institute, University of Washington School of Medicine, University of Michigan, and the Institute of Cancer Research Royal Marsden Hospital.
215-854-2720 @repopter