The role of postoperative radiotherapy for completely resected pIIIA-N2 non-small cell lung cancer patients with different clinicopathological features: a systemic review and meta-analysis

Background: The role of postoperative radiotherapy (PORT) in completely resected pathological stage IIIA-N2 (pIIIA-N2) non-small cell lung cancer (NSCLC) remains controversial. This meta-analysis aimed to assess the effect of PORT in patients with pIIIA-N2 NSCLC on the basis of clinicopathological features. Methods: The PubMed, PubMed Central (PMC), Embase, Web of Science, and Cochrane Library were searched for relevant studies. The main outcomes were overall survival (OS) and disease-free survival (DFS), which were compared using the hazard ratio (HR). Results: One randomized trial and 12 retrospective studies were eligible for the analysis. PORT significantly improved both OS [HR = 0.85; 95% confidence interval (CI): 0.79-0.92] and DFS (HR = 0.57; 95% CI: 0.38-0.85) compared with non-PORT treatment in patients with multiple N2 metastases or multiple N2 station involvement. No significant difference in either OS (HR = 1.03; 95% CI: 0.86-1.24) or DFS (HR = 1.08; 95% CI: 0.70-1.65) was found between PORT and non-PORT groups for patients with single N2 station involvement. No significant heterogeneity was observed. No significant differences in OS were observed between PORT and non-PORT groups for patients of different ages, sex, tumor sizes or pT stages, and histological types. Conclusions: The findings of this meta-analysis supported a role for PORT in patients with completely resected pIIIA-N2 NSCLC having multiple N2 metastases and favored withholding PORT to patients with single N2 station involvement. Further prospective randomized controlled trials are needed to confirm the findings.