Pathologic response rates for breast cancer stages as a predictor of outcomes in patients receiving neoadjuvant chemotherapy followed by breast-conserving surgery

To determine easy-to-use predictors of overall survival (OS), locoregional recurrence (LRR), and distant metastasis (DM) in patients with breast invasive ductal carcinoma (IDC) receiving neoadjuvant chemotherapy (NACT) followed by breast-conserving surgery (BCS), we obtained pathologic response rates (PRRs) for combined primary and nodal diseases (American Joint Committee on Cancer [AJCC] stages) from clinical and pathologic reports, and we used these as predictors. We enrolled patients with IDC who had received NACT followed by BCS. Cox regression analysis was used to calculate hazard ratios (HRs) and confidence intervals (CIs) for the patients’ PRRs; other independent predictors were controlled for or stratified in the analysis. We analyzed 1047 patients with IDC (611, 260, and 176 patients in clinical stages IIB, IIIA, and IIIB-C, respectively) receiving NACT and BCS. After multivariate Cox regression analyses, the adjusted HRs (aHRs; 95% CI) in patients with pathologic complete response (ypT0N0) were 0.26 (0.13–0.56), 0.36 (0.15–0.85), and 0.15 (0.08–0.31) for all-cause mortality, LRR, and DM, respectively. The aHRs (95% CI) in patients with downstaging of AJCC stages were 0.55 (0.35–0.89), 0.91 (0.62–0.96), and 0.63 (0.43–0.91) for all-cause mortality, LRR, and DM, respectively. The aHRs (95% CI) in patients with upstaging of AJCC stages were 1.77 (1.06–2.24), 1.08 (1.03–1.82), and 1.19 (1.07–2.01) for all-cause mortality, LRR, and DM, respectively. The impacts of AJCC-stage PRRs are useful predictive tools and strong predictors for OS, LRR, and DM in patients with breast IDC receiving NACT followed by BCS. •No study has comprehensively analyzed the impact of pathologic response rates (PRRs) for disease stages on overall survival (OS), locoregional recurrence (LRR), or distant metastasis (DM) in patients with breast invasive ductal carcinoma (IDC) receiving neoadjuvant chemotherapy (NACT) and breast-conserving surgery (BCS).•This large cohort study was used to estimate the impact of changes in American Joint Committee on Cancer stages on OS, LRR, and DM in patients with IDC receiving NACT and BCS.•Our data indicate that PRRs, determined using staging records, provide a straightforward means for predicting OS, LRR, and DM. No study has comprehensively analyzed the impact of pathologic response rates (PRRs) for disease stages on overall survival (OS), locoregional recurrence (LRR), or distant metastasis (DM) in patients with breast invasive ductal carci