Effect of postoperative radiotherapy on survival in patients with completely resected and pathologically confirmed stage N2 non-small-cell lung cancer: a systematic review and meta-analysis

BACKGROUND: The role of postoperative radiotherapy (PORT) for patients with completely resected stage N2 non-small-cell lung cancer (NSCLC) has been controversial. This study aimed to investigate the efficacy of PORT and prognosis in these patients. OBJECTIVES: An updated meta-analysis was conducted in this study to investigate the efficacy of PORT and prognosis in patients with completely resected and pathologically confirmed stage N2 NSCLC. DESIGN: This study is a systematic review and meta-analysis. DATA SOURCE AND METHODS: Databases were searched up to 2 March 2022. All trials on patients with completely resected and pathologically confirmed stage N2 NSCLC undergoing PORT were screened, and data indicators in the PORT and non-PORT groups were extracted, respectively. The effect of PORT on overall survival (OS), disease-free survival (DFS), local recurrence-free survival (LRFS), and distant metastasis-free survival (DMFS) was estimated. Subgroup and sensitivity analyses were performed. RESULTS: In all, 20 studies involving 6340 patients were finally included. The PORT significantly increased OS [hazard ratio (HR) = 0.77, 95% CI: 0.71–0.84, p < 0.001), LRFS (HR = 0.63, 95% CI: 0.52–0.76, p < 0.001), and DFS (HR = 0.72, 95% CI: 0.63–0.82, p < 0.001) while it showed no significant difference in improving DMFS (HR = 0.86, 95% CI: 0.71–1.05, p = 0.14). CONCLUSION: Our results suggest that in the postoperative treatment of patients with completely resected and pathologically confirmed stage N2 NSCLC, the addition of PORT provides better local recurrence control and survival benefit, but no benefit for distant metastases. The PORT may be incorporated into the postoperative treatment options for some patients with high-risk factors. However, it needs to be validated by more prospective studies in the future. TRAIL REGISTRATION: CRD42022314095.