Xiao-Ling Xu, Li Dan, Wei Chen, Shuang-Mei Zhu, Wei-Min Mao

Approximately 30% of all cases of nonsmall-cell lung cancer (NSCLC) are of a locally advanced (IIIA or IIIB) stage. However, surgical therapy for patients with stage IIIA (N2) NSCLC is associated with a disappointing 5-year survival rate. The optimal treatment for stage IIIA (N2) NSCLC is still in dispute. A literature search was performed in the PubMed, Embase, and MEDLINE databases (last search updated in March 2015), and a meta-analysis of the available data was conducted. Two authors independently extracted data from each eligible study. A total of nine studies, including five randomized controlled trials and four retrospective studies, were enrolled in this meta-analysis. Significant homogeneity (χ (2)=49.62, P=0.000, I (2)=81.9%) was detected between four of the studies, including a total of 11,948 selected cases. Among the nine studies that investigated overall survival, the pooled hazard ratio (HR) was 0.70 (95% confidence interval (CI): 0.56-0.87; P=0.000). Subgroup analyses were performed according to the study design and the extent of resection. We observed a statistically significant better outcome after lobectomy (pooled HR: 0.52; 95% CI: 0.47-0.58; P=0.000) than after pneumonectomy (pooled HR: 0.82; 95% CI: 0.69-0.98; P=0.028). Unfortunately, there was no significant difference between the randomized controlled studies, as the pooled HR was 0.94 (95% CI: 0.81-1.09; P=0.440). Neoadjuvant chemoradiotherapy or chemotherapy followed by surgery (particularly lobectomy) is superior to following these therapies with definitive chemoradiation or radiotherapy, particularly in patients undergoing lobectomy.