Current National Comprehensive Cancer Network (NCCN) guidelines and Gleason scores cannot reliably stratify patients with risk of prostate cancer for the presence or absence of pathogenic germline variants, according to keynote presentation at the 2017 ASCO Annual Meeting (June 2-6, 2017; Chicago, IL).
Inherited risk for prostate cancer has the potential to lead to more aggressive disease. “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,” said Robert Nussbaum, MD, chief medical officer, Invitae, in a press release (June 12, 2017). “For example, a Lynch syndrome variant may indicate a risk for colon cancer, uterine or ovarian cancer, as well as other cancers.”
Researchers from the Tulane University School of Medicine, in collaboration with researchers from Invitae Corporation, investigated the efficacy of a targeted gene panel in men with inherited risk for prostate cancer and evaluated observed clinical factors’ relationship with current NCCN guidelines for genetic screening. Researchers genetically screened approximately 1150 patients with prostate cancer by using Invitae’s commercially available test – which detects 25 to 79 cancer-related genes, including 14 associated with hereditary prostate cancer.
Researchers found that 17% of patients harbored genetic variations associated with cancer. Seventy-five percent of the variations were detected in genes associated with hereditary prostate cancer, including BRCA1 and BRCA2.
Additionally, 9.5% of detected variations occurred in genes associated with Lynch syndrome, which is an inherent predisposition toward developing several cancers at a young age.
Within the cohort of patients, only 63% (n = 126) were eligible for genetic testing based on currently available NCCN guidelines, whereas 37% (n = 73) would not have qualified.
“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 Oliver Sartor, MD, cancer research professor, Tulane Cancer Center, co-author of the study (June 12, 2017).
These findings may signify a major shortcoming in diagnoses and treatment decisions, authors concluded.—Zachary Bessette