The addition of trastuzumab to adjuvant chemotherapy conferred “substantial and durable improvement in survival” among women with early-stage, HER-2–positive breast cancer, according to a joint analysis of long-term results from randomized two trials.
“This study reflects that excellent science in collaboration between NCI-sponsored cancer cooperative groups and our patients can clearly help improve standards of care,” Edith A. Perez, MD, director of the breast cancer program at Mayo Clinic in Jacksonville, Fla., and a HemOnc Today Editorial Board member, told HemOnc Today. “Some specifics included a very low rate of local recurrence and serious cardiac side effects, even though all patients received anthracyclines prior to paclitaxel–trastuzumab. This regimen is a well-established standard of care regimen for eligible patients.”
Edith A. Perez
Perez and colleagues reviewed data from the NCI-sponsored NSABP B-31 and NCCTGN 9831 trials. The trials included a combined 4,046 patients with HER-2–positive operable breast cancer who received doxorubicin and cyclophosphamide followed by paclitaxel with or without the targeted anti–HER-2 monoclonal antibody trastuzumab (Herceptin, Genentech).
Interim analyses showed reductions in DFS events and trends toward improved OS with trastuzumab. In the current study, Perez and colleagues sought to assess definitive OS results and also provide an update on DFS.
Median follow-up was 8.4 years. Researchers determined the addition of trastuzumab to adjuvant chemotherapy was associated with a 37% relative improvement in OS (HR=0.63; 95% CI, 0.54-0.73). Ten-year OS was 84% among patients who received trastuzumab vs. 75.2% for those who did not.
All patient subgroups benefitted from the addition of trastuzumab to treatment, results showed. HRs for OS were 0.62 (95% CI, 0.52-0.73) among patients with ER-negative and PR-negative tumors, and 0.61 (95% CI, 0.51-0.72) for patients with ER-positive and/or PR-positive tumors.
Researchers also reported a 40% improvement in DFS (HR=0.6; 95% CI, 0.53-0.68). Ten-year DFS was 73.7% among patients who received trastuzumab and 62.2% for those who did not.