Women with human epidermal growth factor receptor 2 (HER2)-positive tumors ≤2 cm derived substantial disease-free and overall survival benefit from adjuvant trastuzumab, a new study published online ahead of print in the Journal of Clinical Oncology has shown.
For the meta-analysis, researchers analyzed data from five of six adjuvant trastuzumab trials in patients with small HER2-positive breast cancer. Primary endpoints were disease-free survival and overall survival.
Results showed that over a median follow-up of 8 years, the cumulative incidence rates in patients with hormone receptor (HR)-positive disease were 17.3% with trastuzumab versus 24.3% with no trastuzumab (P<0.001) for disease-free survival and 7.8% versus 11.6% (P=0.005) for overall survival, respectively.
In patients with HR-positive disease with zero or one positive lymph nodes, disease-free survival was 12.7% with trastuzumab versus 24.0% with no trastuzumab (P=0.005) for disease-free survival and 5.3% compared with 7.4% (P=0.12) for overall survival, respectively.
Researchers found that in patients with HR-negative disease, 8-year cumulative incidence rates were 24.0% versus 33.4% (P<0.001) for disease-free survival and 12.4% versus 21.2% (P<0.001) for overall survival, respectively.
RELATED: Cryopreservation May Preserve Fertility in Breast Cancer
Moreover, in patients with HR-negative tumors with zero or one positive lymph nodes, incidence rates were 20.4% versus 26.3% (P=0.05) for disease-free survival and 8.2% versus 12.2% (P=0.084) for overall survival, respectively.
The findings suggest that patients with HR-positive disease and no more than one positive lymph node treated with trastuzumab may benefit from less aggressive treatment modalities.
- O’Sullivan CC, Bradbury I, Campbell C, et al. Efficacy of adjuvant trastuzumab for patients with human epidermal growth factor receptor 2-positive early breast cancer and tumors ≤2 cm: a meta-analysis of the randomized trastuzumab trials. J Clin Oncol. 2015. [epub ahead of print]. doi: 10.1200/JCO.2015.60.8620.