Trastuzumab achieves slight reduction in recurrence for women with HER2-positive DCIS

The addition of the monoclonal antibody therapy Trastuzumab to radiotherapy did not reach the protocol objective of a 36% reduction in the ipsilateral breast tumor recurrence rate for women with HER2-positive ductal carcinoma in situ (DCIS) on the NRG Oncology clinical trial NSABP B-43. The trial did find a statistically non-significant, modest (19%) reduction in the rate of recurrence among women that received trastuzumab, but this difference was not statistically significant.