Sequential dose-dense 5-fluorouracil, epirubicin and cyclophosphamide followed by docetaxel in patients with early breast cancer with four or more positive lymph nodes.

Aim: The aim of present study was to investigate the feasibility of a densified sequence of FEC75 (5-fluorouracil 600 mg/m2, epirubicin 75 mg/m2, cyclophosphamide 600 mg/m2) and docetaxel 100 mg/m2 (D100) in patients with primary operable high-risk breast cancer.

Methods: Fifty-one consecutive patients with resectable breast cancer and 4 or more positive axillary lymph nodes were enrolled. After a common regimen of 4 cycles of FEC75 given every 14 days, patients received 4 cycles of D100 every 14 days. Prophylactic granulocyte colony-stimulating factor was administered subcutaneously at 5 mg/kg daily from days 5 to 10 to each patient.

Results: The primary endpoint was the proportion of subjects receiving at least 85% of the relative dose intensity (rDI) both in the FEC and docetaxel parts of the regimen. In view of the high percentage of grade 3-4 skin toxicity (32%) observed in the first 25 patients (Group A) during D100 treatment, it was decided to continue the study using a docetaxel dose reduced by 15% (85 mg/m2; D85). This second group of 26 patients was defined as Group B. Of the total 51 patients, 38 (75%) received docetaxel rDI ≥85%, 23/26 patients (88.5%) and 15/25 patients (60.0%) in Group B and Group A, respectively. The observed grade 3-4 hematological and nonhematological toxicities were in line with data from the literature. The only significant difference was the higher percentage of grade 3-4 skin toxicity experienced with D100.

Conclusion: This study failed to demonstrate the feasibility of a dose-dense FEC-D regimen with docetaxel 100 mg/m2. Docetaxel 85 mg/m2 seems to allow a higher rDI than docetaxel 100 mg/m2 but this should be confirmed in a larger cohort of patients.