Management of ovarian and breast cancer risk in non-BRCA HBOC pathogenic variant carriers in a large California health care system

Abstract

PurposeTo describe breast and ovarian cancer risk reduction strategies in the clinical management of women who test positive for non-BRCA hereditary breast and ovarian cancer (HBOC) pathogenic variants compared to those who test positive for pathogenic BRCA variants or have negative germline panel testing. MethodsExamination of imaging and preventive surgeries in women undergoing HBOC genetic testing from 1/1/2015 to 12/31/2018, with follow up to 03/31/2020 in Kaiser Permanente Northern California. ResultsA total of 13,271 tests which included HBOC genes were identified. Rate of bilateral salpingo-oophorectomy after genetic testing were similar for BRCA and the non-BRCA moderate risk ovarian pathogenic variants (PVs) (47.4% vs 54%, p = 0.25). Rates were lower for low risk or unknownrisk non-BRCA PVs (12.8%, p < 0.001, 5.3% (p < 0.001). Rates of surveillance for ovarian cancer with ultrasound and CA 125 in the first year was 63.3% and 64.7% for BRCA PV, 37.5% and 27.1%, for non-BRCA moderate risk PVs and 13.7% and 4.6%, for low-risk PVs. Bilateral mastectomy rates were 19.7% for BRCA PV, 10.1% (p = 0.028) for non-BRCA breast high risk PVs, for moderate risk PVs 7.7% (p < 0.001) and for unknown risk 0.4% (p < 0.001). MRI surveillance rates in the first year similarly were 47.4% for non-BRCA BRCA PV, 43% for breast high risk PV, 39.4% for moderate risk and 4.9% for unknown risk PV. ConclusionSurgical and surveillance strategies are underutilized for HBOC PV, however there is concordance of uptake of preventive strategies with specific risk associated with non-BRCA PVs.