BRCA1/2 and multigene panel testing among metastatic breast, pancreas, prostate, and ovarian cancer patients.

Abstract

e13160 Background: Given the availability of targeted therapies such as PARP inhibitors, patients with metastatic breast, pancreas, prostate, and ovarian cancer are recommended to have germline genetic testing for hereditary cancer syndromes. Completion of genetic testing among this population is understudied. Methods: We performed a retrospective study of 548 patients with stage 4 breast, pancreas, prostate, and ovarian cancer at diagnosis from January 2013-December 2017 identified in the New York Presbyterian Hospital Tumor Registry at Columbia University Irving Medical Center. Data on socio-demographics, clinical factors, and genetic testing completion and results were collected from the medical record. We conducted descriptive statistics. Results: Our study population had a median age of 66 years (range, 23-97) at diagnosis; 61% female; 50% non-Hispanic white/22% Hispanic/15% non-Hispanic black/5% Asian/7% other; 33% private insurance/16% Medicaid/44% Medicare/7% unknown insurance. Primary cancer was 24% breast, 8% ovary, 61% pancreas, and 7% prostate. Only 38 patients were seen by a genetic counselor (7%) and only 50 (9%) had genetic testing performed. Among those who underwent germline testing, 92% had multigene panel testing (median number of genes tested 13.5, range 2-74). Pathogenic variants were detected in 6 patients (12%), of which 4 had a BRCA1/2 mutation, and 26% had a variant of uncertain significance (VUS). Conclusions: We found that only a small percentage of metastatic breast, pancreas, prostate, and ovarian cancer patients underwent genetic testing. Further research is necessary to identify the barriers to genetic testing uptake in metastatic cancer patients. BRCA1/2 and multigene panel testing has important implications in this patient population not only for treatment decisions, but also to increase cascade testing in unaffected family members who may be at risk for malignancy in the future.