Trastuzumab related cardiotoxicity in nonmetastatic breast cancer: A real-world scenario

Background: Trastuzumab, a humanized monoclonal antibody significantly improves outcomes in Her2 neu positive breast cancer. The incidence of cardiotoxicity with trastuzumab is approximately 8-10%. The present study was designed to analyze the incidence and risk factors associated with trastuzmab related cardiotoxicity. Methods: The present study was a single institutional retrospective analysis of the incidence of trastuzumab induced cardiotoxicity in nonmetastatic invasive breast cancer from January 2011 to December 2018. Trastuzumab induced cardiotoxicity (TIC) was defined as symptomatic heart failure or asymptomatic decline in left ventricular ejection fraction (LVEF) by > 10% or LVEF < 50%. Risk factors analysed were BMI (≥30 vs < 30), history of diabetes, hypertension, coronary artery disease (CAD) (yes or no), left sided radiotherapy (RT) and prior anthracycline (yes or no). Results: Data of 246 patients with Her2 neu positive breast cancer was collected. Of these, 117(47.5%) received trastuzumab. The median age at presentation was 51 years (range,28-72). Of 117 patients who received adjuvant trastuzumab TIC was seen in 16(13.6%) patients, asymptomatic LV dysfunction in 9.4% and symptomatic LV dysfunction in 4.2% patients. The median baseline ejection fraction of 65% (range, 56 - 72). The median time to development of TIC was 18.5 (range, 3-52) weeks and median trastuzumab cycle for TIC was 6 (range, 2-16). Presence of ≥ 2 risk factors (20%) had significant impact on incidence of TIC compared to < 2 risk factors (p = 0.04). 10 (62.5%) patients were rechallenged with trastuzumab and 6(37.5%) discontinued trastuzumab. Following rechallenge 1 patient developed asymptomatic decline in EF and 1 developed symptomatic heart failure and were stopped completely. No cardiacrelated mortality was seen.Table214P Risk factors in relation to TICRisk factorTIC PresentTIC absentp ValueBMI ≥ 30 < 302 1414 780.54History of diabetes Yes No3 1321 800.88History of hypertension Yes No8 831 700.2CAD Yes No1 152 990.8Left side RT Yes No9 723 780.012Prior anthracycline Yes No13 365 360.29 Open table in a new tab Conclusions: Approximately 14% developed TIC which was higher in real-world population compared to that seen in clinical trials. Left sided RT to chest and presence of 2 or more risk factors had significant impact on development of TIC. Stringent monitoring of cardiac function to avoid cardiotoxicity and prompt resumption of trastuzumab following recovery may further improve outcomes in nonmetastatic breast cancer. Legal entity responsible for the study: Department of Medical Oncology, NIMS, Punjagutta, Hyderabad, India. Funding: Has not received any funding. Disclosure: All authors have declared no conflicts of interest.