Purpose: Pathological complete response (pCR) to primary chemotherapy is the main determinant for improved disease-free survival (DFS) and overall survival (OS). The primary endpoints of our study were the long-term DFS and OS rates in homogeneously treated stage IIIB breast cancer patients who failed to achieve a pCR (<pCR), in relation to residual tumor burden. The secondary endpoint was the prognostic relevance of hormone receptor (HR) and human epidermal growth factor receptor (HER)-2 status.
Methods: We analyzed 58 of 74 consecutive stage IIIB patients treated between 1996 and 2001 who achieved <pCR following a primary cisplatin, epirubicin, and vinorelbine regimen for up to six cycles. At the time of patient accrual, trastuzumab was not available. After definitive surgery, pathological residual disease remained in 40 (69%) patients in both the breast and axilla, in 14 (24%) patients in only the breast, and in four (7%) patients in only the axilla.
Results: Fifty-eight (78%) of 74 patients achieved <pCR and 16 (22%) had pCR both in the breast and axilla. After a median follow-up of 99 months (range, 72-134 months), in patients with <pCR the estimated 10-year DFS and OS rates were 37.6% and 50.3%, respectively, significantly worse than in the pCR group (p = .003 and p = .008, respectively). Patients with four or more axillary nodes involved had a significantly worse 10-year DFS rate (28.9% versus 62.7%; p = .036). Patients with HR(-) tumors had significantly lower 10-year DFS (17.3% versus 46.4%; p = .018) and OS (17.3% versus 70.2%; p = .002) rates. Overall, the triple-negative (TN) group showed only a marginally significantly worse OS rate (p = .048). HER-2 status alone, in the absence of trastuzumab, did not appear to significantly affect outcomes.
Conclusions: Our data suggest that, in stage IIIB patients who achieve <pCR, the number of residual nodes and HR(-) status are strong predictors of poor outcomes. After a long follow-up time, HER-2 expression does not appear to significantly affect DFS and OS. TN patients showed a trend toward early recurrence and death.