Five-year results of a phase II trial of preoperative 5-fluorouracil, epirubicin, cyclophosphamide followed by docetaxel with capecitabine (wTX) (with trastuzumab in HER2-positive patients) for patients with stage II or III breast cancer

We aimed to increase pathologic complete response (pCR) in patients with invasive breast cancer by adding preoperative capecitabine to docetaxel following 5‐fluorouracil, epirubicin, cyclophosphamide (FEC) (with trastuzumab for patients with HER2‐positive disease) and to evaluate 5‐year disease‐free survival (DFS) associated with this preoperative regimen. Chemotherapy included four cycles of FEC100 (5‐fluorouracil 500 mg/m2, epirubicin 100 mg/m2, cyclophosphamide 500 mg/m2 IV on Day 1 every 21 days) followed by 4 21‐day cycles of docetaxel (35 mg/m2 days 1 and 8) concurrently with capecitabine (825 mg/m2 orally twice daily for 14 days followed by 7 days off) (wTX). For HER2‐positive patients, treatment was modified by decreasing epirubicin to 75 mg/m2 and adding trastuzumab (H) in standard doses (FEC75‐H →wTX‐H). The study objective was to achieve a pCR rate in the breast and axillary lymph nodes of 37% in patients with HER2‐negative breast cancer and of 67% in patients with HER2‐positive breast cancer treated with preoperative trastuzumab. A total of 186 patients were enrolled on study. In an intent‐to‐treat analysis, the pCR rate was 31% (37/118, 95% CI: 24–40%) in the HER2‐negative patients, 24% (15/62, 95% CI: 14–37%) in ER‐positive/HER2‐negative patients, 39% (22/56, 95% CI: 27–53%) in the ER‐negative/HER2‐negative patients, and 46% (29/63, 95% CI: 34–48%) in the HER2‐positive patients. The pCR rate in the 40 trastuzumab‐treated patients was 53% (21/40, 95% CI: 38–67%). Grade 3 and 4 adverse events included neutropenia, leukopenia, diarrhea, and hand‐foot skin reactions. One trastuzumab‐treated patient developed grade 3 cardiotoxicity, and 4 others experienced grade 1–2 decrements in left ventricular function; all five patients’ cardiac function returned to their baseline upon completion of trastuzumab. At 5 years, disease‐free survival was 70% in the HER2‐negative population (78% in ER‐positive/HER2‐negative and 62% in the ER‐negative/HER2‐negative patients) and 80% in the HER2‐positive patients (87% in the trastuzumab‐treated HER2‐positive patients). At 5 years, overall survival was 80% in the HER2‐negative population (88% in ER‐positive/HER2‐negative and 71% in the ER‐negative/HER2‐negative patients) and 86% in the HER2‐positive patients (94.5% in the trastuzumab‐treated HER2‐positive patients). FEC100 (FEC75 with trastuzumab) followed by weekly docetaxel plus capecitabine, with or without trastuzumab is a safe, effective preoperative cytotoxic regimen. However, the addition of capecitabine to docetaxel following FEC, with or without trastuzumab, did not increase pCR rates nor 5‐year DFS over the rates that have been reported with standard preoperative doxorubicin/cyclophosphamide (AC) followed by paclitaxel, with or without trastuzumab. Therefore, the use of capecitabine as part of preoperative chemotherapy is not recommended.