Extended anti-HER2 therapy in early breast cancer: longer beats shorter?

Abstract

One-year duration of adjuvant trastuzumab is the gold standard since 2005. During the last decade many attempts have been made to both increase and reduce the treatment duration. The purpose of this article is to review the current available evidence regarding alternative anti-HER2 therapy durations in the (neo)adjuvant treatment of HER2-positive localized breast cancer patients. According to the majority of published data, shorter trastuzumab schedule has shown a decreased benefit in the overall HER2 population, whereas extending adjuvant trastuzumab, beyond 1 year, does not improve the outcome and is associated with increased cardiac toxicity. However, new challenging questions are raised by the recent results of ExteNet trial, in which sequential introduction of 1 year neratinib after standard trastumab-based therapy improved the outcome, especially in the estrogen receptor-positive subset of patients. To date the standard duration of adjuvant trastuzumab remains 1 year in the adjuvant setting. It is likely that ongoing trials will clarify which patients could benefit from a shorter or a longer treatment. Taking into account patient's specific risk/benefit ratio and new biomarkers, in future, a 'personalized' treatment duration would be warranted.