Association between radiation heart dosimetric parameters, myocardial infarct and overall survival in stage 3 non-small cell lung cancer treated with definitive thoracic radiotherapy.

OBJECTIVES: The aim of this retrospective observational study is to assess the association between various radiation heart dosimetric parameters (RHDPs) and acute myocardial infarct (AMI) and overall survival (OS) outcomes in stage III non-small cell lung cancer (NSCLC) treated with definitive radiotherapy with or without chemotherapy.

MATERIALS AND METHODS: We identified eligible patients treated at two institutions from 2007 to 2014. We linked their electronic medical records to the national AMI and death registries. We performed univariable and multivariable Cox regressions analysis to assess the association between various RHDPs, AMI and OS.

RESULTS: 120 eligible patients were included with a median follow-up of 17.6 months. Median age was 65.5 years. Median prescription dose was 60 Gy. Median mean heart dose (MHD) was 12.6 Gy. Univariable analysis showed that higher MHD (hazard ratio (HR), 1.03; 95% confidence interval (CI), 1.01-1.06; P = .008) and volume of heart receiving at least 5 Gy (V5) (HR, 1.01; 95% CI, 1.00-1.03; P = .042) were associated with increased hazards for AMI. Univariable analysis showed that higher MHD, V5, V25, V30, V40, V50 and dose to 30% of heart volume were associated with increased hazards for death. Multivariable analysis showed that there was no statistically significant association between various RHDPs and OS.

CONCLUSION: The incidence of AMI is low among stage III NSCLC treated with definitive radiotherapy with or without chemotherapy. There is insufficient evidence to conclude that RHDPs are associated with AMI or OS in our study.