Despite evidence from clinical trials showing the efficacy of shorter durations of therapy, most HER2-positive early breast cancer (EBC) patients receive a year of anti-HER2 therapy. A survey of Canadian oncologists was conducted online, with electronic data collection, and the analysis is reported descriptively. Measures collected included current practices with respect to the duration of adjuvant anti-HER2 therapy, perspectives on data regarding shorter durations of treatment, and interest in further trials on this subject. Responses were received from 42 providers across Canada. Half (50%, 21/42) reported having never recommended 6 months of anti-HER2 therapy. The primary reason physicians consider a shorter duration is in response to treatment-related toxicities (76%, 31/41). Most participants (79%, 33/42) expressed the need for more data to determine which patients can be safely and effectively treated with shorter durations. Patient factors such as young age, initial stage, hormone receptor status, and type of neoadjuvant chemotherapy were attributed to reluctance to offer shorter durations of treatment. Many respondents (83%, 35/42) expressed interest in participating in the proposed clinical trial of 6 months of anti-HER2 therapy. In contemporary Canadian practice, 12 months of anti-HER2 therapy remains the primary practice. Future trials are required to better define the role of shorter treatment durations.
Keywords: HER2; breast cancer; trastuzumab.