Feasibility and toxicity of docetaxel before or after fluorouracil, epirubicin, and cyclophosphamide as adjuvant chemotherapy for early-stage breast cancer

604 Background: As adjuvant chemotherapy for breast cancer, the addition of docetaxel to regimens containing anthracyline has been shown to be effective. However, tolerance and safety associated with the administration order of the two drugs have not been evaluated. Methods: Breast cancer patients with node-positive or high-risk patients with node-negative were eligible. The treatment completion rate and toxicity were evaluated in 2 arms who underwent a total of 6 courses of the following regimens: Arm A: 3 courses of fluorouracil 500 mg/m2, epirubicin 100 mg/m2 and cyclophosphamide 500 mg/m2 (FEC100: q3w) followed by 3 courses of docetaxel (DOC100: 100 mg/m2, q3w); and Arm B: 3 courses of DOC100 (q3w) followed by 3 courses of FEC100 (q3w). Results: June 2006 to April 2008, 42 patients were registered. To the present, analysis has been completed in 21 patients in arm A and 21 in arm B. The mean age of patients was 49.1 years and 53.8 years, respectively. In arm A, the stage of cancer was 1 in 4 patients, 2a in 10, and 2b in 7, in arm B, the stage of cancer was 1 in 3 patients, 2a in 9, and 2b in 9. The adjuvant chemotherapy completion rate was 100 % for arm A and 95.2 % for arm B. The relative dose intensity (RDI) was 94.2 % for FEC100 and 97.8 % for DOC100 in arm A, and 98.9 % for DOC100 and 95.2 % for FEC100 in arm B. In arm A, grade 3 or higher hematological toxicity was observed in 9 patients, and febrile neutropenia developed in 3 patients with FEC100. In arm B, grade 3 or higher hematological toxicity was observed in 7 patients, but febrile neutropenia was not noted in any patients. Grade 3 or higher non-hematological toxicity was observed with FEC100 in 2 patients each in the two arms. Grade 1 or 2 edema developed in 11 patients with DOC100 in the two arms. Conclusions: In both arm A and B, adverse events associated with FEC100 were frequently observed but spontaneously recovered, or adequate management was possible by supportive therapy. Adverse events associated with DOC100 were mild. The regimens in both arms A and B were safe regarding adjuvant chemotherapy for early stage breast cancer. However, DOC100 followed by FEC100 may be more tolerable and effective. No significant financial relationships to disclose.