Is the benefit of using adjuvant capecitabine in patients with residual triple-negative breast cancer related to pathological response to neoadjuvant chemotherapy?

Background: Triple-negative-breast-cancer (TNBC) has a poor prognosis if pathologic complete response (pCR) cannot be achieved following neoadjuvant chemotherapy (NAC). The group of patients that benefit most from adjuvant capecitabine remains unclear.

Materials and methods: We analyzed data of 160 consecutive patients with residual TNBC from eight cancer-center. Pathologic response was defined into two groups as having good-pathologic-response (MillerPayneGrading (MPG) IV-III) or poor-pathologic-response (MPG I-II). The characteristics of patients were compared regarding adjuvant capecitabine usage.

Results: Univariate-analysis revealed that age, histology, clinical-stage, tumor-size, lymph-nodes number, menopausal status, and pathological-stage were significantly different between two groups. In multivariate-analysis, menopausal status (p = 0.043) and residual tumor-size (p < 0.001) were found to be independent prognostic factors for pathological response. The hazard-ratio for disease recurrence and death in the poor-response group with adjuvant capecitabine was 2.94 (95% confidence-interval (CI), 1.21 to 7.10; p = 0.016) and 4.080 (95% CI, 1.22 to 13.64; p = 0.022), respectively. DFS (p = 0.58) and OS (p = 0.89) improvements with adjuvant capecitabine were not demonstrated in good-response groups.

Conclusion: This multicenter-study suggested that only the poor-response group to NAC achieved benefit from adjuvant capecitabine. Postmenopausal status and residual tumor-size were related to poor prognosis.