Beneficial effects of postoperative radiotherapy for IIIA‑N2 non‑small cell lung cancer after radical resection analysed using the propensity score‑matching method.

The objective of the present 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. A retrospective review of 288 consecutive patients with resected pIIIA-N2 NSCLC at Beijing Chest Hospital (Beijing, China) was performed. Of these patients, 61 received PORT. The 288 patients were divided into PORT and non-PORT groups according to the treatment received. The baseline characteristics of the two patient groups were balanced using propensity score-matching (PSM; 1:1 matching). In total, 60 patients in the PORT group and 60 patients in the non-PORT group were matched. After PSM, the median survival time of the matched patients was 53 months. The 1-, 3- and 5-year overall survival (OS) rates of the PORT patient group were 95.0, 63.2 and 48.2%, respectively, while those of the non-PORT group were 86.7, 58.3 and 34.5%, respectively, and there was no significant difference between the two groups (P=0.056). The 5-year local recurrence-free survival (LRFS) rate in the PORT group was significantly improved (P=0.001). The effects of PORT on OS and LRFS rates were analysed in patients with different clinicopathological features. For subgroups with multiple N2 stations, N2 positive lymph nodes ≥4 and squamous cell carcinoma, PORT significantly increased the OS and LRFS rates (P<0.05). In conclusion, there was no statistically significant improvement in the 5-year OS rate with PORT overall, but there may be subgroups, such as patients with multiple N2 stations, N2 positive nodes ≥4 and squamous cell carcinoma histology, that could be explored as potentially benefitting from improved 5-year OS and LRFS rates with PORT.