Choice of adjuvant therapy for HER2-positive breast cancer in real clinical practice: analysis of physician preferences in the Russian Federation

Abstract

Adjuvant therapy with trastuzumab made a significant contribution to improving disease-free and overall survival rates in patients with HER2-positive breast cancer. However, in a number of clinical situations the risk of disease recurrence remains increased. Carrying out neoadjuvant treatment followed by post-neoadjuvant therapy, depending on the degree of pathomorphological response, is the modern standard, allowing to cure a significantly larger number of patients. This became possible thanks to the expansion of the arsenal of terget anti-Her drugs and the introduction into real clinical practice of double anti-HER2 blockade (trastuzumab + pertuzumab) and an antibody conjugate with a cytostatic drug – trastuzumab emtansine. To assess actual clinical practice in the Russian Federation, a survey study “Therapy of HER2-positive breast cancer” was conducted. The survey involved 50 specialists from different regions of the country who are directly involved in developing a treatment plan for patients, which allows them to reflect the preferences of leading chemotherapists regarding tactics for HER2-positive breast cancer. This publication reflects the results of part of the survey, devoted to the choice of adjuvant and post-neoadjuvant therapy for HER2-positive breast cancer. Identified a clear positive trend in favor of neoadjuvant treatment followed by post-neoadjuvant therapy using modern targeted drugs such as pertuzumab and trastuzumab emtansine. The survey results show that 68% of patients with RCB-II–III residual tumor receive post-neoadjuvant trastuzumab emtanzine, in 2021 this figure was only 24%. The absolute majority of patients who have not received neoadjuvant therapy, but have N2–3 stage, receive double anti-HER2 therapy with trastuzumab + pertuzumab in the adjuvant setting. High adherence to the therapy was noted, as 97% of patients complete the planned course of T-DM1, and 91.2% of patients complete a year of adjuvant anti-HER2 therapy. These figures are noticeably higher than the indicators of registration studies. Issues of effectiveness come to the fore in choosing therapy. Issues of drug availability remain relevant, but are not decisive. The survey also revealed factors that were not obvious at first glance and influenced treatment results.