Extracapsular extension in prediction of the efficacy of postoperative radiotherapy in the treatment of stage III_A-N₂ non-small cell lung cancer

Objective: To investigate the value of extracapsular extension (ECE) in prediction of the efficacy of postoperative radiotherapy (PORT) in the treatment of stage III_A-N₂ non-small cell lung cancer (NSCLC). Methods: From 2008 to 2009, 220 patients with stage III_A-N₂ NSCLC who received surgical treatment were enrolled as subjects. All patients received postoperative chemotherapy and 43 out of them received PORT. Those patients were divided into ECE (+) group and ECE (-) group, which were further divided into subgroups according to whether PORT was applied or not. Progression-free survival (PFS) and overall survival (OS) rates were calculated using the Kaplan-Meier method and analyzed using log-rank test. Univariate and multivariate prognostic analyses were conducted using the log-rank test and the Cox model, respectively. Results: The univariate analysis showed that the ECE (-) group had significantly improved PFS and OS rates than the ECE (+) group (P = 0.000, 0.000). In the ECE (+) group, there were no significant differences in PFS or OS rate between the PORT subgroup and the non-PORT subgroup (P = 0.584, 0.723). In the ECE (-) group, the PORT subgroup had a significantly improved PFS rate than the non-PORT subgroup (P = 0.039), while there was no significant difference in OS rate between the two subgroups (P = 0.125). The multivariate analysis indicated that ECE was an independent prognostic factor for PFS and OS rates in patients with stage III_A-N₂ NSCLC (P = 0.001, 0.020). Conclusions: ECE is an independent prognostic factor for stage III_A-N₂ NSCLC and promises to provide a basis for the use of PORT in the treatment of stage III_A-N₂ NSCLC. (authors)