Pathological tumor response to neoadjuvant chemotherapy using anthracycline and taxanes in patients with triple-negative breast cancer.

Although triple-negative breast cancer (TNBC) is associated with a poor prognosis, recent reports have indicated that a higher proportion of TNBC patients shows a pathological complete response (pCR) to neoadjuvant chemotherapy (NAC) than is the case for non-TNBC patients. The aim of this study was to identify markers that predict pCR to NAC in TNBC patients, and to clarify prognostic factors that affect the outcome of TNBC patients with residual disease (RD) after NAC. Among 44 TNBC patients who received anthracycline- and taxane-based combination NAC, we analyzed the relationship between pathological response and clinicopathological characteristics, including immunohistochemical parameters (cytokeratin 5/6, epidermal growth factor receptor, Ki-67, p53, breast cancer susceptibility protein 1 and topoisomerase IIα). We also assessed the prognostic impact on patients with RD by analyzing the correlation between disease-free survival (DFS) and clinicopathological parameters. Sixteen patients (36%) achieved a pCR and log-rank test showed that these patients had a significantly more favorable outcome than patients with RD (DFS, P=0.00184; overall survival, P=0.0080). Among the clinicopathological parameters examined, none was correlated with pathological response, with the exception of p53. Patients with immunohistochemical overexpression of p53 more frequently achieved a pCR than those without p53 overexpression (P=0.0484). In the patients with RD, the Cox proportional hazards model showed that the presence of lymphovascular invasion was significantly associated with shorter DFS (hazard ratio, 13.333; 95% CI 1.587-111.111; P=0.0171). p53 overexpression may be a key predictor of a favorable response to NAC. Since patients with RD, particularly those positive for lymphovascular invasion, had an extremely poor outcome, novel therapeutic approaches for these patients are warranted.