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.


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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.

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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. 

Reference

  1. 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.