BRCA1/2 testing rates in epithelial ovarian cancer: a focus on the untested patients

BACKGROUND: Since 2015, Dutch guidelines have recommended BRCA1/2 pathogenic variant testing for all patients with epithelial ovarian cancer. Recently, recommendations shifted from germline testing to the tumor-first approach, in which tumor tissue is tested first, and subsequent germline testing is performed only in those with BRCA1/2 tumor pathogenic variants or a positive family history. Data on testing rates and on characteristics of patients missing out on testing remain scarce. OBJECTIVE: To evaluate BRCA1/2 testing rates in patients with epithelial ovarian cancer and compare testing rates of germline testing (performed from 2015 until mid-2018) versus tumor-first testing (implemented mid-2018). METHODS: A consecutive series of 250 patients diagnosed with epithelial ovarian cancer between 2016 and 2019 was included from the OncoLifeS data-biobank of the University Medical Center Groningen, the Netherlands. Testing rates were analyzed for the overall study population and for germline testing (period I) and tumor-first testing (period II) separately. Characteristics of tested and untested patients were compared and predictors for receiving testing were assessed with multivariable logistic regression. RESULTS: Median age was 67.0 years (IQR 59.0–73.0) and 173 (69.2%) patients were diagnosed with high-grade serous carcinoma. Overall, 201 (80.4%) patients were tested. In period I, 137/171 (80.1%) patients were tested and in period II this was 64/79 (81.0%). Patients with non-high-grade serous carcinoma were significantly less likely to receive BRCA1/2 testing than patients with high-grade serous carcinoma (OR=0.23, 95% CI 0.11 to 0.46, p<0.001). CONCLUSIONS: The results show that BRCA1/2 testing rates are suboptimal and suggest that clinicians may not be choosing to test patients with epithelial ovarian cancer with non-high-grade serous ovarian carcinoma, although guidelines recommend BRCA1/2 testing in all patients with epithelial ovarian cancer. Suboptimal testing rates limit optimization of care for patients with epithelial ovarian cancer and counseling of potentially affected relatives.