Prostate cancer testing guidelines fail to cover important genetic features of patients with the disease, a shortcoming that could be having a major impact on diagnosis and treatment decisions, according to a study.
The team presented the results, titled “Need for re-evaluation of current guidelines based on results from germline genetic testing in prostate cancer,” at the American Society of Clinical Oncology (ASCO) annual meeting in Chicago, June 2-6. Conference judges designated it a Best of ASCO presentation.
“Some of the genes implicated in prostate cancer are also associated with other conditions, making it vital for patients and their families to have genetic information,” Dr. Robert Nussbaum, Invitae’s chief medical officer, said in a press release. “For example, a BRCA variant may be passed on to a daughter, putting her at risk for breast cancer, or a Lynch syndrome variant may indicate a risk for colon cancer, uterine or ovarian cancer, as well as other cancers.
“Now that genetic testing is accessible and affordable, we must reevaluate how we are using this powerful information to help improve healthcare for patients and their families,” Nussbaum added.
Researchers did genetic screenings of nearly 1,150 prostate cancer patients. They used Invitae’s commercially available genetic test, which identifies the presence of 25 to 79 cancer-related genes, including 14 associated with hereditary prostate cancer.
Seventeen percent of the patients carried genetic variations associated with cancer, and 1 percent, or 12 patients, carried two gene variations. About 75 percent of the variations were found in genes previously associated with hereditary prostate cancer. They included the two genes tested under current guidelines, BRCA1 and BRCA2, which were present in 34 percent of patients.
In addition, 9.5 percent of the detected variations occurred in genes associated with Lynch syndrome. The inherited condition predisposes patients to increased risk of developing several cancers at a young age.
Despite the evidence of many cancer-associated genetic variations in prostate cancer patients, only 63 percent were eligible for genetic testing under current guidelines. This means that 37 percent of patients with prostate cancer-associated mutations would have not qualified for testing.
“This study solidly underscores the need to reevaluate how we test prostate patients for genetic variants associated with disease, in terms of both expanding who we offer testing to and broadening the list of genes we test them for beyond just BRCA1 and BRCA2,” said Dr. Oliver Sartor, a cancer research professor at Tulane Cancer Center in New Orleans, who co-authored the study.
“Patients who have variants in these genes may be more likely to have aggressive disease, and genetic information about a number of genes may have implications for treatment decisions,” Sartor added.