Effect of postoperative radiotherapy on outcome in resectable stage IIIA-N2 non-small-cell lung cancer: an updated meta-analysis

BACKGROUND: In a previous meta-analysis-based modeling study, it was hypothesized that modern postoperative radiotherapy (PORT) may improve both local recurrence and overall survival (OS) in stage IIIA-N2 non-small-cell lung cancer (NSCLC). There were only four single-arm trials with a total of 357 patients. As other trials have provided new and controversial data, we performed this updated meta-analysis to test the hypothesis. PATIENTS AND METHODS: Systematic reviews in Medline, Cochrane, and Science Direct up to December 2015 identified publications exploring the efficacy of PORT in resectable stage IIIA-N2 NSCLC. RESULTS: Overall, 16 trials comprising 3278 patients were included. There was a significant benefit in favor of PORT regarding OS [hazard ratio (HR): 0.73, 95% confidence interval (CI): 0.58-0.92, P=0.008; absolute benefit at 5 years=8%], disease-free survival (HR: 0.70, 95% CI: 0.60-0.83, P<0.0001), and locoregional recurrence-free survival (HR: 0.37, 95% CI: 0.24-0.58, P<0.0001). Restriction of the analysis to trials with induction and/or adjuvant chemotherapy led to similar results. PORT significantly decreased the risk of local recurrence (risk ratio: 0.64, 95% CI: 0.50-0.82, P=0.0006) and DM (risk ratio: 0.74, 95% CI: 0.62-0.88, P=0.0005), and the absolute risk differences were 13 and 14%, respectively. CONCLUSION: The addition of PORT, with or without chemotherapy, significantly improves local control and survival in patients with resectable stage IIIA-N2 NSCLC.