Response-Guided Neoadjuvant Chemotherapy for Breast Cancer

Abstract

Purpose We investigated disease-free survival (DFS) and overall survival (OS) after response-guided neoadjuvant chemotherapy in patients with early breast cancer. Patients and Methods We treated 2,072 patients with two cycles of docetaxel, doxorubicin, and cyclophosphamide (TAC) and randomly assigned early responders to four (n = 704) or six (n = 686) additional TAC cycles, and early nonresponders to four cycles of TAC (n = 321) or vinorelbine and capecitabine (NX; n = 301) before surgery. Results DFS was longer in early responders receiving TAC × 8 than in those receiving TAC × 6 (hazard ratio [HR], 0.78; 95% CI, 0.62 to 0.97; P = .026), and in early nonresponders receiving TAC-NX than in those receiving TAC × 6 (HR, 0.59; 95% CI, 0.49 to 0.82; P = .001). Exploratory analysis showed that DFS after response-guided chemotherapy (TAC × 8 or TAC-NX) was significantly longer (HR, 0.71; 95% CI, 0.60 to 0.85; P < .003), as was OS (HR, 0.79; 95% CI, 0.63 to 0.99; P = .048), than on conventional chemotherapy (TAC × 6). DFS was longer after response-guided chemotherapy in all hormone receptor–positive tumors (luminal A HR = 0.55, luminal B [human epidermal growth factor receptor 2 (HER2) negative] HR = 0.40, and luminal B [HER2 positive] HR = 0.56), but not in hormone receptor–negative tumors (HER2 positive [nonluminal] HR = 1.01 and triple negative HR = 0.87). Pathologic complete response did not predict these survival effects. pCR predicted an improved DFS in triple-negative (HR = 6.67), HER2-positive (nonluminal; HR 5.24), or luminal B (HER2-negative) tumors (HR = 3.74). Conclusion This exploratory analysis suggests that response-guided neoadjuvant chemotherapy might improve survival and is most effective in hormone receptor–positive tumors. If confirmed, the response-guided approach could provide a clinically meaningful advantage for the neoadjuvant over the adjuvant approach in early breast cancer.