Adjuvant Chemotherapy May be Waived for Breast Cancer Nonresponders to Neoadjuvant Chemotherapy: A Population-Based Large Cohort Study.

Purpose: This study aimed to evaluate the efficacy of adjuvant chemotherapy (AC) in breast cancer patients who did not respond to neoadjuvant chemotherapy (NAC) following surgery.

Method: A retrospective analysis was performed using a large, population-based cohort to identify breast cancer patients who underwent radical surgery following NAC without achieving a response. Kaplan-Meier analysis and Cox regression models were employed to assess clinical outcomes and prognostic factors. Propensity score matching (PSM) was applied to compare outcomes between patients receiving AC vs. those who did not, followed by subgroup analyses.

Results: A total of 1866 patients were included, of whom 1030 received postoperative AC. The median follow-up time was 68.0 months. Patients receiving AC had a median overall survival (OS) of 124.0 months, compared to 93.0 months for those not receiving AC. However, multivariate analysis indicated that receiving postoperative AC was not an independent prognostic factor. Furthermore, PSM analysis indicated no improvement in long-term survival for patients receiving postoperative AC compared to those not receiving it. Subgroup analysis further supported these findings, revealing no significant differences in OS between AC and Non-AC cohorts across various subgroups.

Conclusion: These findings suggest that breast cancer patients unresponsive to NAC may derive limited benefit from subsequent AC. Therefore, the decision to administer AC should be carefully considered, and alternative therapeutic strategies should be explored for these patients.