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

Purpose: 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.

Patients And Methods: 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.

Results: 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.

Conclusion: 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.