Anthracyclines, taxanes, and alkylating agents are among the most active agents in treatment of adjuvant breast cancer (BC), but the optimal schedule for their administration is unknown. We performed an adjuvant trial to compare the sequential regimen of doxorubicin with cyclophosphamide (AC) followed by docetaxel (ie, AC>T) with the combination regimen of TAC.

Women with node-positive, human epidermal growth factor receptor 2-nonamplified, operable BC were stratified by number of axillary nodes and hormone receptor status and were randomly assigned to adjuvant chemotherapy with six cycles of TAC (75/50/500 mg/m² every 3 weeks) or four cycles of AC (60/600 mg/m² every 3 weeks) followed by four doses of docetaxel at 100 mg/m² every 3 weeks (AC>T). After completion of chemotherapy, radiation therapy was given as indicated, and patients with hormone receptor (HR) -positive disease received adjuvant hormonal therapy with tamoxifen and/or aromatase inhibitors.

In 30 months, 3,298 patients were enrolled (n = 1,649 in each arm). The major baseline characteristics were well balanced between the groups. At a median follow-up of 65 months, estimated 5-year disease-free survival rates were 79% in both groups (log-rank P = .98; hazard ratio [HR], 1.0; 95%CI, 0.86 to 1.16), and 5-year overall survival rates for both arms were 88% and 89%, respectively (log-rank P = .37; HR, 0.91; 95% CI, 0.75 to 1.11). TAC was associated with more febrile neutropenia and thrombocytopenia, and AC>T was associated with more sensory neuropathy, nail changes, and myalgia. The incidence of neutropenic infection was similar in both groups.

The sequential and combination regimens incorporating three drugs were equally effective but differed in toxicity profile.