Prognostic value of pathologic complete response after primary chemotherapy in relation to hormone receptor status and other factors

Purpose To evaluate whether hormonal receptor (HR) status can influence the prognostic significance of pathologic complete response (pCR). Patients and Methods This retrospective analysis included 1,731 patients with stage I to III noninflammatory breast cancer treated between 1988 and 2005 with primary chemotherapy (PC). Ninety-one percent of patients received anthracycline-based PC, and 66% received additional taxane therapy. pCR was defined as no evidence of invasive tumor in the breast and axillary lymph nodes. Results Median age was 49 years (range, 19 to 83 years). Sixty-seven percent of patients (n = 1,163) had HR-positive tumors. A pCR was observed in 225 (13%) of 1,731 patients; pCR rates were 24% in HR-negative tumors and 8% in HR-positive tumors (P < .001). A significant survival benefit for patients who achieved pCR compared with no pCR was observed regardless of HIR status. In the HR-positive group, 5-year overall survival (OS) rates were 96.4% v 84.5% (P = .04) and 5-year progression-free survival (PFS) rates were 91.1 % v 65.3% (P < .0001) for patients with and without pCIR, respectively. For the H R-negative group, 5-year OS rates were 83.9% v 67.4% (P = .003) and 5-year PFS rates were 83.4% v 50.0% (P < .0001) for patients with and without pCIR, respectively. After adjustment for adjuvant hormonal treatment, HR status, clinical stage, and nuclear grade, patients who achieved a pCR had 0.36 times the risk of death. Conclusion pCR is associated with better outcome regardless of HIR status in breast cancer patients who receive PC.