Purpose: To evaluate the efficacy of trastuzumab in patients with node-positive breast cancer treated with surgery, adjuvant chemotherapy, radiotherapy, and hormone therapy if applicable.
Patients and methods: Three thousand ten patients with operable node-positive breast cancer were randomly assigned to receive adjuvant anthracycline-based chemotherapy with or without docetaxel. Patients who presented human epidermal growth factor receptor 2 (HER2) -overexpressing tumors were secondary randomly assigned to either a sequential regimen of trastuzumab (6 mg/kg every 3 weeks) for 1 year or observation. The primary end point was disease-free survival (DFS).
Results: Overall 528 patients were randomly assigned between trastuzumab (n = 260) and observation (n = 268) arm. Of the 234 patients (90%) who received at least one administration of trastuzumab, 196 (84%) received at least 6 months of treatment, and 41 (18%) discontinued treatment due to cardiac events (any grade). At the date of analysis (October 2007), 129 DFS events were recorded. Random assignment to the trastuzumab arm was associated with a nonsignificant 14% reduction in the risk of relapse (hazard ratio, 0.86; 95% CI, 0.61 to 1.22; P = .41, log-rank stratified on pathologic node involvement). Three-year DFS rates were 78% (95% CI, 72.3 to 82.5) and 81% (95% CI, 75.3 to 85.4) in the observation and trastuzumab arms, respectively.
Conclusion: After a 47-month median follow-up, 1 year of trastuzumab given sequentially after adjuvant chemotherapy was not associated with a statistically significant decrease in the risk of relapse.