Cardiovascular toxicity in patients treated with immunotherapy for metastatic non-small cell lung cancer: A SEER-medicare study

Objectives In recent years immunotherapy has escalated to frontline treatment options for metastatic non-small cell lung cancer. Cardiovascular toxicity from chemotherapeutic agents is well described in this patient population with common underlying risk factors like smoking. We explored cardiovascular toxicity form the addition of immune checkpoint inhibitors to traditional chemotherapy. Materials and Methods This is a retrospective study from SEER-Medicare datasets which represents 34 % of the US population. This study included patients age ≥ 65 years-old with newly diagnosed metastatic non-small cell lung cancer between the years 2013 and 2015. Patients were divided into 2 cohorts, one who received traditional chemotherapy only (control arm) and the others who received immune checkpoint inhibitors in addition to traditional chemotherapy (study arm). The primary endpoint was the hazards of new cardiovascular toxicity in the study versus the control arm. Results We identified 6405 patients who met our study criteria. Of these, 5730 patients received chemotherapy only while 675 patients received chemotherapy and immune checkpoint inhibitors. Results showed that the hazard ratio for all cardiovascular toxicity was 0.81 (95 % CI:0.72−0.91, p = 0.0003) in patients who received immune checkpoint inhibitors with chemotherapy. Among the subgroups, hazards ratio for acute coronary syndrome was 0.82 (95 % CI: 0.64–1.05, p = 0.10), hazards ratio for heart failure was 0.74 (95 % CI: 0.62−0.88, p = 0.0007), hazards ratio for cardiac arrhythmia was 0.72 (95 % CI: 0.63−0.82, p < 0.0001) and hazards ratio for heart blocks was 0.48 (95 % CI: 0.30−0.76, p < 0.0001). There was no significant difference in hazards for cardiomyopathy, pericarditis, and myocarditis between the two cohorts. Patients above 75 years, with comorbidities and pre-existing heart disease, were at higher risk. Conclusions Results from this study are reassuring that adding immune checkpoint inhibitors to chemotherapy is safe and does not result in increased cardiovascular toxicity but instead showed lower hazards.