Adjuvant Chemotherapy with Sequential or Concurrent Anthracycline and Docetaxel: Breast International Group 02-98 Randomized Trial

Background: Docetaxel is more effective than doxorubicin for patients with advanced breast cancer. The Breast International Group 02-98 randomized trial tested the effect of incorporating docetaxel into anthracycline-based adjuvant chemotherapy and compared sequential vs concurrent administration of doxorubicin and docetaxel.

Methods: Patients with lymph node-positive breast cancer (n = 2887) were randomly assigned to one of four treatments: 1) sequential control (four cycles of doxorubicin at 75 mg/m2, followed by three cycles of cyclophosphamide, methotrexate, and 5-fluorouracil [CMF]); 2) concurrent control (four cycles of doxorubicin at 60 mg/m2 plus cyclophosphamide at 600 mg/m2, followed by three cycles of CMF); 3) sequential docetaxel (three cycles of doxorubicin at 75 mg/m2, followed by three cycles of docetaxel at 100 mg/m2, followed by three cycles of CMF); 4) concurrent docetaxel (four cycles of doxorubicin at 50 mg/m2 plus docetaxel at 75 mg/m2, followed by three cycles of CMF). The primary comparison evaluated the efficacy of including docetaxel regardless of schedule and was planned after 1215 disease-free survival (DFS) events (ie, relapse, second primary cancer, or death from any cause). Docetaxel and control treatment groups were compared by log-rank tests, and hazard ratios (HR) of DFS events were calculated by Cox modeling. All statistical tests were two-sided.

Results: Due to a lower-than-anticipated rate of relapse, this analysis was performed after 5 years with 732 events. Patients in control arms had a 5-year DFS of 73% (95% confidence interval [CI] = 70% to 75%). Docetaxel treatment resulted in an improvement in DFS of borderline statistical significance compared with control treatment (HR = 0.86, 95% CI = 0.74 to 1.00; P = .05). However, DFS in the sequential docetaxel arm was better than that in the concurrent docetaxel arm (HR = 0.83, 95% CI = 0.69 to 1.00) and in the sequential control arm (HR = 0.79, 95% CI = 0.64 to 0.98).

Conclusions: Incorporating docetaxel into anthracycline-based therapy resulted in an improvement in DFS that was of borderline statistical significance. However, important differences may be related to doxorubicin and docetaxel scheduling, with sequential but not concurrent administration, appearing to produce better DFS than anthracycline-based chemotherapy.