(ChemotherapyAdvisor) – No evidence was found that extending adjuvant doxorubicin and cyclophosphamide or single-agent paclitaxel from 4 to 6 cycles improves clinical outcome in women with resected primary breast cancer and 0 to 3 positive nodes, the Cancer and Leukemia Group B 40101 study reported in a rapid communication in the Journal of Clinical Oncology online July 23.
The study enrolled 3,171 women with operable breast cancer and 0 to 3 positive nodes (94% were node-negative and 6% had 1 to 3 positive nodes) between 2002 and 2008 and randomly assigned them to either 4 or 6 cycles of either doxorubicin and cyclophosphamide or paclitaxel. Patients were stratified by estrogen receptor/progesterone receptor, HER2, and menopausal status.
The 4-year relapse-free survival at a median follow-up of 5.3 years was 90.9% for 6 cycles and 91.8% for 4 cycles (adjusted HR 1.03 [95% CI, 0.84–1.28]; P=0.77). The 4-year overall survival was 95.3% for 6 cycles and 96.3% for 4 cycles [HR 1.12 [95% CI, 0.84 to 1.49]; P=0.44). No interaction was observed between treatment duration and chemotherapy regimen, estrogen-receptor/progesterone receptor, or HER2 status on relapse-free or overall survival.
This study demonstrates that “…patients can be spared longer and more toxic treatment with these regimens without fear of compromising breast cancer outcome,” Lawrence N. Shulman, MD, of the Dana-Farber Cancer Institute, Boston, MA, and colleagues concluded.