There is no standard treatment for patients with small, node-negative HER2-positive breast cancer. In a study reported in The
New England Journal of Medicine (online, 8 January 2015)
, US researchers tested a regimen of adjuvant paclitaxel and trastuzumab in 406 such patients. Combination treatment was for 12 weeks followed by nine months of trastuzumab monotherapy.
The median follow-up period was 4.0 years and the three-year rate of survival free from invasive disease was 98.7% (95% confidence interval 97.6 to 99.8). There were 12 relapses, of which two were due to distant metastatic breast cancer, and the rate of serious adverse effects was low, with a heart failure incidence of 0.5%.
While the researchers say that patient outcomes were better than expected, they concede that their study does not support trastuzumab-based chemotherapy in all patients with small HER2-positive tumours.
 Tolaney SM, Barry WT, Dang CT et al. Adjuvant paclitaxel and trastuzumab for node-negative, HER2-positive breast cancer. New England Journal of Medicine 2015;372(2):134–141. doi:10.1056/NEJMoa1406281.