Abstract PS4-12-30: Overall survival and prognostic factors in patients with triple-negative breast cancer treated with adjuvant capecitabine: real-world experience in a peruvian cohort

Abstract INTRODUCTION Triple-negative breast cancer is a subtype with a poor prognosis, characterized by high rates of relapse and early mortality. Adjuvant therapy with capecitabine in patients with residual disease after neoadjuvant therapy has shown a benefit in overall survival (OS), as reported in the CREATE-X study with a 5-year OS of 79%; however, there is limited evidence in Latin America (LATAM) from real-world clinical practice. OBJECTIVE To analyze the results in patients with non-metastatic triple-negative breast cancer treated with adjuvant capecitabine at a Peruvian cancer center, and to identify prognostic factors associated with overall survival. METHODS A retrospective cohort study was conducted of patients diagnosed with non-metastatic triple-negative breast cancer treated between 2020 and 2023 at a Peruvian cancer center. Clinical, histopathological, and therapeutic variables were collected. OS and its association with clinical and pathological characteristics were estimated using Kaplan-Meier curves. RESULTS A total of 199 patients were evaluated, 67% of whom received adjuvant capecitabine. The median age was 47 years (range 42-56), with most (98.5%) having an ECOG performance status of 0-1. Regarding anatomical variables, the most frequent were T3-T4 (65%) and N1 (45%); the most common clinical stage was IIIB (31%). Among the pathological characteristics, the most frequent were ductal histology (73%), histological grade 3 (68%), with an average ki67 of 60%. The median time between the end of neoadjuvant chemotherapy and surgery was 51 days (30.5-79.5). During neoadjuvant therapy, 25% of patients used carboplatin. Regarding surgery, most patients underwent mastectomy (81%), with operative findings of ypT2 (37%), ypN0 (43.3%), and pathological stage III. During adjuvant therapy, 96% of patients received radiotherapy. With a median follow-up of 31 months (9-103), OS rates at 12, 36, and 60 months were estimated at 99%, 87%, and 58%, respectively, with no median OS reached. Conservative surgery (vs. mastectomy, NR vs. 15 months, p=0.043), absence of lymphovascular invasion (vs. presence, p=0.022), and involvement of ypT1-ypT2 lymph nodes (vs. ypT3, 80% vs. 48%, p=0.002) were associated with higher OS. Regarding recurrence patterns, recurrence was observed in 39% of patients, with distant recurrence being the most frequent in 74%. The most frequent site of metastasis was the lung. CONCLUSION In this Peruvian cohort of patients with triple-negative breast cancer, adjuvant capecitabine demonstrated an increase in OS at 5 years, showing aggressive disease behavior and a high tumor burden, predominantly locally advanced. Conservative surgery, absence of lymphovascular invasion, and low lymph node involvement were associated with higher OS. These findings consolidate capecitabine as part of the standard treatment for post-neoadjuvant residual disease in a Latin American population. Citation Format: Miguel Chirito, Guillermo Valencia, Zaida Morante, Patricia Rioja, Sandra Adrianzén, Karen Cruz, Antonio Nuñez, Claudia Castillo, Jorge Sánchez, Astrid Cuyutupa, Daniel Garcia, Andrea Recines, Raúl Mantilla, Karina Aliaga, Connie Rabanal, Jorge Dunstan, Silvia Neciosup, Tatiana Vidaurre. Overall survival and prognostic factors in patients with triple-negative breast cancer treated with adjuvant capecitabine: real-world experience in a peruvian cohort abstract. In: Proceedings of the San Antonio Breast Cancer Symposium 2025; 2025 Dec 9-12; San Antonio, TX. Philadelphia (PA): AACR; Clin Cancer Res 2026;32(4 Suppl):Abstract nr PS4-12-30.