Abstract PO2-02-04: The Impact of Statins on Breast Cancer Specific Mortality in a Diverse Patient Population with Stage I-III Hormone Receptor Positive, HER2 Negative Breast Cancer

Abstract Hormone receptor-positive (HR+), HER2 negative (HER2−) breast cancer has a long-term risk of recurrence, compared with other breast cancer subtypes, which ultimately impacts mortality outcomes. Although adjuvant endocrine therapy plays an integral role in risk reduction, disparities persist—with Black women experiencing higher mortality rates compared to White women. Multiple studies have demonstrated that statin use can lead to a reduction in breast cancer mortality, but there is limited information in relation to the impact of statins among diverse patient populations in the United States. To assess whether statin use is associated with an improvement in breast cancer-specific mortality (BCSM), we conducted a large, observational study in women aged 66 and older diagnosed with Stage I–IIIC HR+, HER2- breast cancer between 2013 and 2017. We identified eligible women using the SEER-Medicare database and linked them to the BRIDGE (BReast cancer Investigation of Disparities in GEorgia) cohort, a survivorship cohort of the Georgia Cancer Registry. Patients needed to be continuously enrolled in Medicare Parts A, B, and D in the 12 months following a breast cancer diagnosis. We used Cox proportional hazards models to estimate the impact of statin use within 12 months of diagnosis on BCSM with adjustment for age, stage, and race using multivariable-adjusted hazard ratios (HRs). A total of 2483 participants were identified, and of those, 303 (12.2%) were statin users, 383 (15.4%) were non-Hispanic Black women, and 1564 (63%) resided in census tract with greater than or equal to 10% poverty levels at the time of diagnosis. Distribution of age, stage, and race were similar between statin and non-statin users. Of the statin users, 41/303 (13.5%) were non-Hispanic Black women. The majority of statin users were prescribed lipophilic statins alone (169; 55.8%), and atorvastatin was the most commonly prescribed statin. There was no association between statin use and BCSM (HR 1.09; 95% CI 0.62-1.90) in the multivariable-adjusted model. Although preliminary results suggest that there is no association between statin use and BCSM among women with Stage I–IIIC HR+, HER2− breast cancer, further analyses are planned to explore statin use as a time-varying exposure, which may provide additional insights into the potential relationship between statin use and BCSM. In addition, analyses examining potential heterogeneity by race, tumor and treatment characteristics, and comorbidities are forthcoming. Given the low cost and relative accessibility of statins, we anticipate these findings will inform the clinical management of women with operable breast cancer, increasing parity in outcomes and potentially narrowing race disparities. Citation Format: Ruth Sacks, Maya Bliss, Micah Streiff, Leah Moubadder, Maret Maliniak, Tsion Armidie, Lindsay Collin, Kevin Kalinsky, Lauren McCullough. The Impact of Statins on Breast Cancer Specific Mortality in a Diverse Patient Population with Stage I-III Hormone Receptor Positive, HER2 Negative Breast Cancer abstract. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO2-02-04.