Postoperative intensity-modulated radiation therapy reduces local recurrence and improves overall survival in III-N2 non-small-cell lung cancer: A single-center, retrospective study

Purpose 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). Materials and Methods 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 illustrated in these two groups. The sites of failure based on the lobe of the primary tumor in two groups were described. Results 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%). Conclusion PORT remarkably reduced local recurrence and improved OS in stage III-pN2 NSCLC, especially in the multiple-station pN2 group.