Cause of death among patients with non-small cell lung cancer treated with postoperative radiation therapy (PORT).

e20555 Background: The indications for post-operative radiation therapy (PORT) in locally advanced non-small cell lung cancer (NSCLC) remain undefined and a major concern is the perceived risk of increased mortality from cardiopulmonary causes. The purpose of this study was to quantify the rate of cardiopulmonary death in patients with resected NSCLC receiving PORT using a large national database. Methods: Using the Surveillance, Epidemiology, and End Results (SEER) database for lung cancer, patients with Stage IIIA or Stage IIIB NSCLC according to the 6th AJCC edition treated with surgery followed by PORT, who also received chemotherapy were identified. Cause of death was categorized as due to lung cancer, other cancer, cardiac, pulmonary, or other and reported as a percentage of total deaths at one and 2 years. Kaplan-Meier survival analysis was done to compare overall survival between Stage IIIA and IIIB patients. Results: From 2004 to 2015, 4387 patients with stage IIIA and IIIB meeting the eligibility criteria were identified. The median age at diagnosis was 65 years old, most patients were male (53%), Caucasian (83%), had adenocarcinoma (54.8%), stage IIIA disease (69%), and N2 disease (78%). The median overall survival for Stage IIIA and IIIB patients was 39 months and 27 months respectively (p < 0.001). Among the 2586 patients that died during the study period, the most common COD was lung cancer (81.3%). Cardiac and pulmonary COD occurred in 86 patients (3.3% of deaths) and 84 patients (3.2% of deaths) respectively, whereas 158 patients (6.1%) died from other cancers and 154 (5.9%) from other causes. There were 77 deaths from cardiopulmonary cause at 2 years (1.7% of patients and 2.9% of deaths). Cardiopulmonary COD was more common in patients with stage IIIB compared to IIIA disease (4.9% vs 3.3% of deaths, p < 0.001). Lung cancer was the most common COD both at 1 and 2 years (85%) whereas cardiopulmonary was the COD in 5.2% of patients at 1 year and 5.1% at 2 years. Conclusions: This analysis showed a low cardiopulmonary mortality from PORT in the first 2 years. The role for adjuvant radiotherapy remains undefined and treatment decisions for patients with resected stage III NSCLC should be guided by co-morbidities and the competing risk for death from lung cancer.