BRCA1/2 germline testing among eligible persons with breast cancer in Washington state: A retrospective study using state cancer registry and claims data.

Abstract

154 Background: Clinical practice guidelines have recommended germline testing certain groups of breast cancer patients (men, younger women, and triple negative) for pathogenic BRCA1/2 mutations since 1996. We linked cancer registry records with enrollment and claims records from public and commercial insurers in Washington state to assess factors associated with BRCA1/2 testing among eligible persons with breast cancer. Methods: The database consisted of Washington SEER and state cancer registry records linked with claims records from commercial insurers (Premera Blue Cross, Regence Blue Shield), Medicare, Medicaid, and the Washington State Employee Benefit Plan. Eligible patients were diagnosed with breast cancer between 2017-2019 and were age <= 50 female, any age male, or with triple negative cancer. Other inclusion criteria included first primary cancer, alive at least 3 months following diagnosis, and continuous insurance enrollment from 2 months prior to 24 months following diagnosis. We used multivariable logistic regression to examine factors associated with BRCA1/2 testing. In a secondary analysis, we examined whether receipt of testing was associated with bilateral mastectomy. Results: The study population included 1,358 women and 43 men (80.2% were non-Hispanic White, 4.1% non-Hispanic Black, 11.7% non-Hispanic Asian, and 4.9% Hispanic.) The insurance composition was as follows: 56% commercial, 15% Medicare, 19% Medicaid; 10% multiple insurers. Overall, 63% received BRCA1/2 testing. Factors that were significantly associated with testing are shown in the table. In the secondary regression model, the association between BRCA1/2 testing and bilateral mastectomy was positive (OR 1.45, 95% CI 1.07-1.98). Conclusions: Despite a trend towards more testing over time, BRCA1/2 germline testing remains underutilized among persons who are eligible for testing, with significant disparities among Medicaid and Medicare enrollees. Testing may influence management, but further study is required. Patients would benefit from more effective integration of clinical guidelines into practice.[Table: see text]