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

Abstract

Objective To investigate the value of extracapsular extension (ECE) in prediction of the efficacy of postoperative radiotherapy (PORT) in the treatment of stage ⅢA—N2 non-small cell lung cancer (NSCLC). Methods From 2008 to 2009, 220 patients with stage ⅢA—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 ⅢA—N2 NSCLC (P=0.001, 0.020). Conclusions ECE is an independent prognostic factor for stage ⅢA—N2 NSCLC and promises to provide a basis for the use of PORT in the treatment of stage ⅢA—N2 NSCLC. Key words: Carcinoma, non-small cell lung/postoperative chemotherapy; Carcinoma, non-small cell lung/postoperative radiotherapy; Extracapsular extension; Prognostic factor