Purpose: To determine long-term outcomes in a clinical trial evaluating the role of taxane type and schedule in operable breast cancer and evaluate the impact of obesity and black race on outcome.
Patients and methods: A total of 4,954 eligible women with stage II to III breast cancer treated with four cycles of doxorubicin plus cyclophosphamide were randomly assigned to receive paclitaxel or docetaxel every 3 weeks for four doses or weekly for 12 doses using a 2 × 2 factorial design. The primary end point was disease-free survival (DFS). Results are expressed as hazard ratios (HRs) from Cox proportional hazards models. All P values are two sided.
Results: When compared with the standard every-3-week paclitaxel arm, after a median follow-up of 12.1 years, DFS significantly improved and overall survival (OS) marginally improved only for the weekly paclitaxel (HR, 0.84; P = .011 and HR, 0.87; P = .09, respectively) and every-3-week docetaxel arms (HR, 0.79; P = .001 and HR, 0.86; P = .054, respectively). Weekly paclitaxel improved DFS and OS (HR, 0.69; P = .010 and HR, 0.69; P = .019, respectively) in triple-negative breast cancer. For hormone receptor-positive, human epidermal growth factor receptor 2-nonoverexpressing disease, no experimental arm improved OS, and black race and obesity were associated with increased risk of breast cancer recurrence and death.
Conclusion: Improved outcomes initially observed for weekly paclitaxel were qualitatively similar but quantitatively less pronounced with longer follow-up, although exploratory analysis suggested substantial benefit in triple-negative disease. Further research is required to understand why obesity and race influence clinical outcome in hormone receptor-positive disease.
Trial registration: ClinicalTrials.gov NCT00004125.
© 2015 by American Society of Clinical Oncology.