Abstract PO3-03-08: Use of adjuvant Capecitabine after neoadjuvant chemotherapy: A Cohort Study among Elderly Patients with Early-Stage Triple-Negative Breast Cancer

Abstract Background: The use of capecitabine in the adjuvant setting in patients with residual disease after neoadjuvant chemotherapy has been incorporated into practice based on the results of the CREATE-X trial. We evaluate utilization patterns of adjuvant capecitabine use, its association with outcomes, and subsequent hospitalizations and emergency room (ER) visits among elderly patients with early-stage triple-negative breast cancer (TNBC). Methods: We identified patients aged ≥66, diagnosed with early-stage TNBC between 2010 and 2017 in the SEER and Texas Cancer Registry (TCR)-linked Medicare databases. All patients were treated with neoadjuvant chemotherapy for localized or regional-stage disease. All patients had continuous enrollment in Medicare Parts A 95% CI: 0.11–0.60; p =0.002). Among capecitabine users, 3-year OS was 46% and 78% for patients who received 1-3 and ≥4cycles of capecitabine, respectively (p 0.001). The 3-year estimate of BCSS was 43% and 85% respectively (p 0.001). After multivariable adjustment for comorbidity score, stage, and propensity score, receiving ≥4 cycles of capecitabine was associated with decreased risk of death (HR=0.29; 95%CI 0.13–0.63, p=0.002) and breast cancer-specific death (HR=0.15; 95%CI: 0.05–0.51, p=0.002) compared to receiving 1-3 cycles. Twenty-seven (28%) patients had ER/hospitalization during capecitabine treatment; median time from initial capecitabine claim to ER/hospitalization was 24 days (IQ 13-39). The median number of capecitabine cycles was 3 (IQR 2-5) and 5 (IQR 3-8) for those with and without ER/hospitalization (p=0.02). The most common diagnosis codes associated with ER/hospitalization included pleural effusion, GI symptoms, pneumonia, and acute kidney failure. A higher comorbidity score at diagnosis was associated with an increased risk of ER/hospitalization (HR=2.76; 95%CI 1.05-7.28, p=0.04). Conclusion: We demonstrate an increasing trend in capecitabine utilization among elderly patients with early-stage TNBC. Although the limited sample size hindered a conclusive analysis, more cycles of capecitabine were associated with improved survival outcomes. Notably, a significant proportion of patients undergoing capecitabine treatment experienced ER/hospitalizations. These findings contribute valuable information on the risks and benefits of capecitabine treatment, aiding evidence-based decision-making to prevent serious complications. Citation Format: Marija Sullivan, Xiudong Lei, Catalina Malinowski, Sharon Giordano, Marianna Chavez. Use of adjuvant Capecitabine after neoadjuvant chemotherapy: A Cohort Study among Elderly Patients with Early-Stage Triple-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 PO3-03-08.