Post-Operative Radiotherapy (PORT) is Associated with Better Survival in Non-Small Cell Lung Cancer with Involved N2 Lymph Nodes: Results of an Analysis of the National Cancer Data Base
Menée à partir de données portant sur 2 115 patients traités par résection et chimiothérapie pour un cancer du poumon non à petites cellules avec envahissement ganglionnaire (stade pN2) diagnostiqué entre 2004 et 2006, cette étude évalue, du point de vue de la survie globale, l'intérêt d'une radiothérapie post-opératoire
Introduction : Use of post-operative radiotherapy (PORT) in non-small cell lung cancer (NSCLC) remains controversial. Limited data indicate that PORT may benefit patients with involved N2 nodes. This study evaluates this hypothesis in a large retrospective cohort treated with chemotherapy and contemporary radiation techniques. Methods : The National Cancer Data Base (NCDB) was queried for patients diagnosed 2004-2006 with resected NSCLC and pathologically involved N2 (pN2) nodes also treated with chemotherapy. Multivariable Cox proportional hazards model was used to assess factors associated with overall survival (OS). Inverse probability of treatment weighting (IPTW) using the propensity score was used to reduce selection bias. OS was compared between patients treated with vs. without PORT using the adjusted Kaplan-Meier estimator and weighted log-rank test based on IPTW. Results : 2 115 patients were eligible for analysis. 918 (43.4%) received PORT, 1197 (56.6%) did not. PORT was associated with better OS (median survival time (MST) 42 months with PORT vs. 38 months without, p=.048). This effect was significant in multivariable and IPTW Cox models (HR 0.87, 95% CI 0.78-0.98, p=.026, and HR 0.89, 95% CI 0.79-1.00, p=.046, respectively). No interaction was seen between the effects of PORT and number of involved lymph nodes (p=.615). Conclusions : PORT was associated with better survival for patients with pN2 nodes also treated with chemotherapy. No interaction was seen between benefit of PORT and number of involved nodes. These findings reinforce the benefit of PORT for N2 disease in modern practice using the largest, most recent cohort of chemotherapy-treated pN2 patients to date. Copyright (C) 2014 by the European Lung Cancer Conference and the International Association for the Study of Lung Cancer.