Impact of the extent of pathologic complete response on outcomes after neoadjuvant chemotherapy

Background and Objective With advances in systemic therapies for breast cancer, responses to neoadjuvant chemotherapy (NAC) have increased. Pathologic complete response (pCR) after NAC is an independent prognostic factor. We examined the impact of breast and/or lymph node (LN) pCR on survival. Methods From a prospectively maintained database, 202 women were identified with LN-positive breast cancer who underwent NAC then surgery. Clinicopathologic factors and survival were compared between four groups: breast/LNs pCR, node-only pCR, breast-only pCR, and residual disease (RD). Results Forty-eight (23.8%) patients had breast/LNs pCR, 43 (21.3%) node-only pCR, 5 (2.5%) breast-only pCR, and 106 (52.5%) had RD. There was no difference in age, stage, or breast operation between groups. With a median follow-up of 48.2 months, patients with any pCR had improved disease-free survival (DFS) (HR, 0.3; 95% CI, 0.157-0.572) and OS (HR, 0.192; 95% CI, 0.057-0.652) compared with RD patients. There were no significant differences in DFS (log-rank P = .18) and OS (log-rank P = 0.12) between patients with node-only pCR, breast-only pCR, and breast/LNs pCR. Conclusion In node-positive breast cancer patients receiving NAC, any pCR was associated with improved survival vs RD. The anatomic site of pCR did not impact survival. This suggests that any favorable response to NAC has prognostic value.