To investigate the association between survival and postoperative radiotherapy (PORT) in patients with resected non-small-cell lung cancer (NSCLC).

Within the Surveillance, Epidemiology, and End Results database, we selected patients with stage II or III NSCLC who underwent a lobectomy or pneumonectomy. Only those patients coded as receiving PORT or observation were included. To account for perioperative mortality, we excluded patients who survived less than 4 months. As a result of our inclusion criteria, we selected a total of 7,465 patients, with a median follow-up time of 3.5 years for patients still alive.

Predictors for the use of PORT included age less than 50 years, higher American Joint Committee on Cancer stage, T3-4 tumor stage, larger tumor size, advanced node stage, greater number of lymph nodes involved, and a ratio of lymph nodes involved to lymph nodes sampled approaching 1.00. On multivariate analysis, older age, T3-4 tumor stage, N2 node stage, male sex, fewer sampled lymph nodes, and greater number of involved lymph nodes had a negative impact on survival. The use of PORT did not have a significant impact on survival. However, in subset analysis for patients with N2 nodal disease (hazard ratio [HR] = 0.855; 95% CI, 0.762 to 0.959; P = .0077), PORT was associated with a significant increase in survival. For patients with N0 (HR = 1.176; 95% CI, 1.005 to 1.376; P = .0435) and N1 (HR = 1.097; 95% CI, 1.015 to 1.186; P = .0196) nodal disease, PORT was associated with a significant decrease in survival.

In a population-based cohort, PORT use is associated with an increase in survival in patients with N2 nodal disease but not in patients with N1 and N0 nodal disease.