Abstract PS4-09-18: Factors with Immunotherapy Use Among Patients with Triple Negative Breast Cancer in California: A Population-Based Study

Abstract BACKGROUND: Immunotherapy with immune checkpoint inhibitors has been approved for triple negative breast cancer (TNBC) since 2019. However, uptake of new therapies may be delayed by a variety of factors that affect access, such as facility level factors and individual demographic factors such as race/ethnicity and age. We investigated individual-, facility- and neighborhood-level factors associated with use of immunotherapy among females diagnosed with TNBC in California from 2019-2021 using statewide cancer registry data. METHODS: We used the California Cancer Registry to identify 7,495 women ages 18 and over diagnosed with first primary microscopically confirmed malignant TNBC diagnosed in 2019-2021. We used registry data about immunotherapy use to infer use of immune checkpoint inhibitor. Patient-level factors include age at diagnosis, AJCC stage, grade, other treatments received, marital status, and health insurance status. We used multivariable logistic regression to calculate odds ratios (OR) and 95% confidence intervals (CI) factors associated with immunotherapy use, including independent variables that were statistically significant at p70 vs. Age