Optimizing Adherence to Adjuvant Trastuzumab Therapy: a Prospective Controlled Clinical Trial of Monitoring Cardiotoxicity

Aim: Cardiotoxicity is the main reason for premature discontinuation of neo/adjuvant trastuzumab therapy. Guidelines currently recommend follow-up of left ventricular ejection fraction (LVEF) measured either by multiple gated acquisition scan (MUGA) or echocardiography (ECHO), without specifying the preferred method and an interruption of treatment if LVEF declines ≥10%. In a prospective study we assessed the separate and combined impact of MUGA, ECHO, and a comprehensive cardio-oncology team approach in detecting cardiotoxicity thus safely minimizing premature therapy discontinuation. Methods: Breast cancer patients undergoing post-anthracycline trastuzumab neo/adjuvant therapy were included. MUGA, ECHO and clinical evaluation of potential cardiotoxicity was performed at baseline, after 4, 8 and 12 months. Therapy discontinuation because of cardiotoxicity was considered not only based on LVEF decline as determined by either method alone, but after thorough assessment of both methods and clinical status by a dedicated cardio-oncology team. Results: From October 2011 to November 2013 a total of 92 patients were included, all female, median age was 53 (35-76) years. We found a significant overall correlation between MUGA-LVEF and ECHO-LVEF (Interclass correlation coefficient 0.87, 95% CI 0.81-0.91, p Conclusions: We found a significant correlation between MUGA-LVEF and ECHO-LVEF. Determination of LVEF decline by MUGA or ECHO may overestimate the incidence of clinically significant trastuzumab-induced left ventricular dysfunction. Findings of our study suggest that therapy discontinuation might be minimized by integrating both methods with a comprehensive cardio-oncology team approach in case of LVEF decline detected by the preferred routinely used method. Disclosure: All authors have declared no conflicts of interest.