Changes in Invasive Breast Carcinomas after Neoadjuvant Chemotherapy Can Influence Adjuvant Therapeutic Decisions

Neoadjuvant chemotherapy (NACT) can change invasive breast carcinomas (IBC) and influence the patients' overall survival time (OS). We aimed to identify IBC changes after NACT and their association with OS.

IBC data in pre- and post-NACT samples of 86 patients were evaluated and associated with OS.

Post-NACT tumors changed nuclear pleomorphism score (p=0.025); mitotic count (p=0.002); % of tumor-infiltrating inflammatory cells (p=0.016); presence of in situ carcinoma (p=0.001) and lymphovascular invasion (LVI; p=0.002); expression of estrogen (p=0.003), progesterone receptors (PR; p=0.019), and Ki67 (p=0.003). Immunohistochemical (IHC) profile changed in 26 tumors (30.2%, p=0.050). Higher risk of death was significatively associated with initial tumor histological grade III (hazard ratio [HR], 2.94), high nuclear pleomorphism (HR, 2.53), high Ki67 index (HR, 2.47), post-NACT presence of LVI (HR, 1.90), luminal B-like profile (HR, 2.58), pre- (HR, 2.26) and post-NACT intermediate mitotic count (HR, 2.12), pre- (HR, 4.45) and post-NACT triple-negative IHC profile (HR, 4.52). On the other hand, lower risk of death was significative associated with pre- (HR, 0.35) and post-NACT (HR, 0.39) estrogen receptor-positive, and pre- (HR, 0.37) and post-NACT (HR, 0.57) PR-positive. Changes in IHC profile were associated with longer OS (p=0.050). In multivariate analysis, pre-NACT grade III tumors and pre-NACT and post-NACT triple negative IHC profile proved to be independent factors for shorter OS.

NACT can change tumor characteristics and biomarkers and impact on OS; therefore, they should be reassessed on residual samples to improve therapeutic decisions.