Real-world comparison of the impact of adjuvant capecitabine in women with high-risk triple-negative breast cancer after neoadjuvant chemotherapy

Abstract

Background: Adjuvant capecitabine (adjC) is recommended for patients with triplenegative breast cancer (TNBC) and poor response to neoadjuvant chemotherapy. Despite evidence of benefit, this therapy is not available in situations of limited resources, such as in the Brazilian public health system. Methods: A retrospective observational cohort study was conducted in Princess Margaret (PM) Cancer Centre in Toronto, Canada, and in A.C. Camargo Cancer Center (AC) in São Paulo, Brazil. Patients with TNBC who had completed neoadjuvant chemotherapy (taxane and/or anthracycline) followed by surgery, with a high residual cancer burden (RCB-II or RCB-III) and received at least 1 cycle of adjC in PM or had active surveillance (AS) in AC were evaluated. A descriptive comparison was made between PM and AC. Recurrence free survival (RFS), overall survival (OS), and safety profile were explored descriptively. Chi-Square test and Mann-Whitney test were used to assess categorical and continuous variables data, while Kaplan-Meier survival and Cox-regression were used for time-to-event analyses. Results: From 06/17 to 03/19, 21 patients received adjC in PM and from 04/02 to 03/19, 70 patients had AS in AC. Starting dose of capecitabine was 1000 mg/m2 bid. Seven patients (43.8%) completed 8 cycles, two (12.5%) received 6 cycles and for the remaining patients therapy is ongoing. The median follow-up was 23 months (range 1.9-36 months). At PM 76.2% of the patients were free from recurrence or death and 81% were alive at 3 years. The mean RFS was better in the adjC group (mean 30.8 months vs 20.0 months HR: 0.23; p=0.045). Mean OS was 29 months in adjC group vs 28 months in AS (HR: 1.48; p=0.610). Common adverse events were hand-foot syndrome, fatigue, diarrhea, nausea and anemia. Dose reduction, delay to next chemotherapy cycle or discontinuance of treatment were necessary in 13 (61.9%) patients. Conclusions: Outcome of patients receiving adjC at PM was better than those on AS in AC, suggesting benefit fromthis treatment in a real-world setting. AdjC is an inexpensive, widely available and well tolerated oral chemotherapy and should be considered an option for improvement of care even in public health systems of less developed countries.