Clinical impact of postoperative radiotherapy in pIII-N2 non-small cell lung cancer after complete resection followed by adjuvant chemotherapy: a systematic review and meta-analysis

Theoretically, postoperative radiotherapy (PORT) could reduce the risk of local recurrence and further improve survival outcomes. This study aimed to evaluate the clinical impact of PORT on patients with pIII-N2 non-small cell lung cancer (NSCLC) after complete resection followed by adjuvant chemotherapy. A systematic literature search was performed in November 2022 to identify randomized controlled trials (RCTs) that compare PORT with observation in patients with pIII-N2 NSCLC using PubMed, Embase, and the Cochrane Central Register of Controlled Trials. This meta-analysis is in accordance with the recommendations of the PRISMA statement. The main outcomes were overall survival (OS), disease-free survival (DFS), and local recurrence rates, which were compared using hazard ratios (HRs). Five RCTs involving 1,138 patients were included: 572 patients in the PORT group and 566 patients in the observation group. The methodological quality of the five RCTs was high. Pooled analysis revealed that PORT decreased local recurrence rate [odds ratio =0.53, 95% confidence interval (CI): 0.40-0.70]. However, PORT did not improve median DFS (HR =0.93, 95% CI: 0.80-1.08) and OS (HR =0.94, 95% CI: 0.78-1.14). Compared to adjuvant chemotherapy alone, additional PORT was significantly associated with a reduced local recurrence rate. However, neither DFS nor OS benefited from PORT in patients with pIII-N2 NSCLC who had undergone complete resection.