Prognostic Impact of Node-Spreading Pattern in Surgically Treated Small-Cell Lung Cancer: A Multicentric Analysis.

Abstract

Although surgery in selected small-cell lung cancer (SCLC) patients has been proposed as a part of multimodality therapy, so far, the prognostic impact of node-spreading pattern has not been fully elucidated. To investigate this issue, a retrospective analysis was performed. From 01/1996 to 12/2012, clinico-pathological, surgical, and oncological features were retrospectively reviewed in a multicentric cohort of 154 surgically treated SCLC patients. A multivariate Cox proportional hazard model was developed using stepwise regression, in order to identify independent outcome predictors. Overall (OS), cancer-specific (CSS), and Relapse-free survival (RFS) were calculated by Kaplan-Meier method. Overall, median OS, CSS, and RFS were 29 (95% CI 18-39), 48 (95% CI 19-78), and 22 (95% CI 17-27) months, respectively. Lymphadenectomy was performed in 140 (90.9%) patients (median number of harvested nodes: 11.5). Sixty-seven (47.9%) pN0-cases experienced the best long-term survival (CSS: 71, RFS: 62months; p<0.0001). Among node-positive patients, no prognostic differences were found between pN1 and pN2 involvement (CSS: 22 vs. 15, and RFS: 14 vs. 10months, respectively; p=0.99). By splitting node-positive SCLC according to concurrent N1-invasion, N0N2-patients showed a worse CSS compared to those cases with combined N1N2-involvement (N0N2: 8months vs. N1N2: 22months; p=0.04). On the other hand, the number of metastatic stations (p=0.80) and the specific node-level (p=0.85) did not affect CSS. At multivariate analysis, pN+ (HR: 3.05, 95% CI 1.21-7.67, p=0.02) and ratio between metastatic and resected lymph-nodes (RL, HR: 1.02, 95% CI 1.00-1.04, p=0.03) were independent predictors of CSS. Moreover, node-positive patients (HR: 3.60, 95% CI 1.95-6.63, p<0.0001) with tumor size ≥5cm (HR: 1.85, 95% CI 0.88-3.88, p=0.10) experienced a worse RFS. In selected surgically treated SCLC, the long-term survival may be stratified according to the node-spreading pattern.