NICE (CG 80) recommends the use of adjuvant trastuzumab for one year or until disease recurrence, in women with HER2-positive early invasive breast cancer following surgery, chemotherapy, and radiotherapy. This recommendation was based on data that demonstrated the one-year trastuzumab regimen was cost effective in the adjuvant setting.
Results from the HERceptin Adjuvant (HERA; 8 year follow up) confirm the use of adjuvant trastuzumab for one year. Of note, researchers found that during the first few years of follow-up, the two-year treatment group had slightly superior disease-free survival compared with the one- year group (89•1% vs 86•7% at 3 years after randomisation), but this difference decreased with further follow-up. At the time of the study analysis, an identical number of disease-free survival events had occurred in the two trastuzumab groups (367; HR 0•99, 95% CI 0•85–1•14), and similar numbers of patients had died (196 in the two-year group and 186 in the one-year group). No difference in either disease-free or overall survival was recorded between the groups that received trastuzumab. The 2-year treatment group was also associated with greater cardiac toxicity (8.2% vs 4.9%).
The optimum duration of adjuvant trastuzumab remains unknown, and studies evaluating treatment durations shorter than 12 months, or dual HER2 blockade, are currently underway and could lead to further improvements in the adjuvant treatment of HER2-positive breast cancer.