Incidence and severity of cardiotoxicity in metastatic renal cell carcinoma (RCC) patients treated with targeted therapies

4610 Background: Almost all patients with advanced RCC are treated with therapies targeting the hypoxia inducible factor axis. The potential for these agents to cause cardiovascular (CV) toxicity has been increasingly recognized but the overall incidence and extent have not been well described. We sought to identify and characterize the incidence and severity of CV toxicity among RCC patients treated with targeted therapies. Methods: Between 2004 and 2011, all RCC patients treated with targeted therapies directed against the VEGF or mTOR axes were identified at our institution. The incidence of hypertension, left ventricular (LV) dysfunction, changes in serum markers of CV toxicity (e.g., troponin I, NT-proBNP) and heart failure were assessed and graded according to the Common Terminology Criteria for Adverse Events (CTCAE v.4.0). Results: Cardiovascular toxicity developed in 116 of 159 patients (73%). Excluding hypertension, 52 of 159 (33%) developed cardiovascular toxicity. Cardiac toxicity ranged from asymptomatic drops in LV ejection fraction (LVEF) to rises in NT-proBNP to severe heart failure. Asymptomatic cardiotoxicity as defined by decrease in LVEF or increase in NT-proBNP occurred in 43 patients (27%). Symptomatic heart failure (grade 2-3) and grade 3-4 decrease in LVEF each occurred in 4%. Sunitinib was the most frequently used and most common offending agent, with 66 of 101 sunitinib-treated patients (65%) developing a form of CV toxicity, or 32 of 101 (32%) excluding hypertension. However, it was notable that CV toxicity was observed in 68%, 66%, and 51% of patients treated with bevacizumab, sorafenib, and pazopanib as well. The mTOR inhibitors elicited significantly less CV toxicity, but sample sizes were small. Conclusions: Cardiovascular toxicity is an important adverse event related to targeted therapy administration. Close monitoring for the development of CV toxicity with the use of these agents should become standard of care as early detection of asymptomatic patients could preempt symptomatic toxicity and reduce treatment-related morbidity and mortality.