Beneficial Effect of Postoperative Radiotherapy for IIIA-N2 Non-small Cell Lung Cancer After Radical Resection Analyzed Using Propensity Score Matching Method

Abstract Background. The objective of this study was to investigate the role of postoperative radiotherapy (PORT) after radical resection of stage IIIA-N2 non-small cell lung cancer (NSCLC). Subgroups of patients who benefited from PORT were evaluated.Methods. A retrospective review of 288 consecutive patients with resected pIIIA-N2 NSCLC at Beijing Chest Hospital was performed. Sixty-one patients additionally received PORT. The patients were divided into PORT and non-PORT groups according treatment received. Baseline characteristics of the two patient groups were balanced by propensity score matching (PSM) (1:1 matching). Sixty patients in the PORT group and sixty patients in non-PORT group were matched. Results. After PSM, the median survival time of the matched patients was 53 months. The 1-, 3- and 5-year overall survival (OS) rates of PORT patient group were 95.0%, 63.2% and 48.2%, respectively, compared to non-PORT group of 86.7%, 58.3% and 34.5% (P = 0.056). The 5-year local recurrence free survival rate (LRFS) in PORT group was significantly improved (P = 0.001). The effect of PORT on OS and LRFS were analyzed in patients with different clinicopathological features. For subgroups with multiple N2 station, N2 positive lymph nodes≥4 and squamous cell carcinoma, PORT significantly increased OS and LRFS (P < 0.05).Conclusions. PORT moderately improves the 5-year OS of patients with stage IIIA-N2 NSCLC after radical operation, and significantly improves the 5-year LRFS. These results suggest that PORT should be considered for patients with multiple N2 station, N2 positive lymph nodes≥4 and squamous cell carcinoma.