To determine the postoperative effects of radiotherapy (PORT) on the local recurrence-free survival (LRFS) and overall survival (OS) of stage III-N2 non-small-cell lung cancer (NSCLC). 183 patients with resected stage III-pN2 NSCLC from Hunan Cancer Hospital between 2013 and 2016 were divided into two groups for postoperative chemotherapy (POCT) (n = 105) or combination chemotherapy and radiotherapy (POCRT) (n = 78). The LRFS and OS were compared and the factors affecting local recurrence were

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... llustrated in these two groups. The sites of failure based on the lobe of the primary tumor in two groups were described. PORT leads to a strikingly lower risk for local recurrence and brought superior OS benefit. For different pN2 Subclassification, Patients with multiple-station pN2 ± pN1 disease had the worst LRFS (11 months) and single-station pN2 + multiple station pN1 disease had a relatively short LRFS (24 months) in group POCT. Short LRFS is correlated with multiple-station pN2, older age (Y > 55), patients with a high positive LN ratio > 1/3 and a poor tumor histological differentiation degree. In group POCT, the most frequent failure site occurs at the ipsilateral hilum (21.0%), the bronchial stump (20.0%), followed by LNs4R (19.0%), LNs4L (18.1%), LNs7 (15.2%), most of left-sided tumors more frequently involved the contralateral mediastinum, whereas the ipsilateral recurrences dominated for right-sided tumors, especially for LNs4R. In group POCRT, the highest failure site was the bronchial stump (11.5%), followed by LNs4L (8.97%), LNs1 (7.69%), the ipsilateral hilum (6.41%) and LNs4R (6.41%). PORT remarkably reduced local recurrence and improved OS in stage III-pN2 NSCLC, especially in the multiple-station pN2 group.