Comparison of three testing strategies for germline genetic testing for homologous recombination deficiency mutations in women with epithelial ovarian cancer (198)

Abstract

<b>Objectives:</b> One in five women with epithelial ovarian cancer (EOC) will have an inherited germline mutation impacting cancer outcomes and familial risk. National recommendations exist for testing all EOC patients for inherited homologous recombination deficiency mutations, yet testing rates remain low, and which strategy results in the highest testing rates is unclear. Point-of-care testing, where gynecologic oncology practices offer abbreviated counseling with in-office testing, may increase testing rates. We aimed to compare rates among three different testing strategies used in our practice over time at a single academic institution. <b>Methods:</b> All patients with EOC were identified from the electronic medical record (EMR) using diagnostic codes for malignant neoplasm of the ovary at an urban academic gynecologic oncology practice from January 2015 to December 2020. IRB approval was obtained, and an EMR review was performed to analyze trends in genetic counseling and testing rates across three different practice models: embedded genetic counselor within the clinic (before May 2017), referral-out for genetic counseling (May 2017-October2017) and point-of-care genetic testing (after October 2017). Descriptive statistics and Chi-square tests were used to analyze data. <b>Results:</b> We identified a total of 431 patients with EOC. Patients were predominantly White (88%), older women (average age 67.9), with Medicare (58%) or private insurance (39%). Most patients had the advanced-stage disease (63% Stage III, 17% Stage IV) with high-grade serous (77%) histology. Germline <i>BRCA1</i> or <i>2</i> mutations were identified in 10.5% and 4.5% of patients, respectively, and 10.6% of patients were diagnosed with a different homologous recombination deficiency gene mutation. Significant differences in genetic testing rates were identified by strategy (<i>p</i> < 0.0001). During the embedded genetic counselor period, 66% (173/263) of patients underwent genetic testing. The testing rate dropped to 13% (13/104) when patients were referred out, then improved to 65% (160/245) when point-of-care testing was initiated. Over the entire study period, 80% of patients eventually received germline genetic testing, with 44% of patients initially not tested (40/91) undergoing catch-up testing after initiation of point-of-care testing. <b>Conclusions:</b> Germline genetic testing rates for women with EOC were comparable for embedded genetic counselor and point-of-care testing strategies and lowest during the referral-out period. Point-of-care testing has allowed catch-up testing over time, whereas the referral-out strategy presented a substantial barrier to testing. To achieve guideline-concordant care, point-of-care testing with post-test counseling represents a feasible strategy for gynecologic oncology practices where access to an embedded genetic counselor is not possible.