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 HR 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 pCR, respectively. For the HR-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 pCR, 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 HR status in breast cancer patients who receive PC.