83P Radiotherapy improves the survival of patients with extensive disease small cell lung cancer: A propensity matched analysis of surveillance, epidemiology and end results database

Abstract

Background: The survival advantage of radiotherapy (RT) for patients with extensive disease small cell lung cancer (ED-SCLC) has not been adequately evaluated. Methods: We analyzed stage IV SCLC patients enrolled from a large data from the Surveillance, Epidemiology, and End Results (SEER) registry through January 2010 and January 2012. Propensity score (PS) analysis with 1:1 matching and the nearest neighbor matching method were performed to ensure well-balanced characteristics of all comparison groups. Kaplan-Meier and Cox proportional hazardous model were used to evaluate the overall survival (OS), cancer-specific survival (CSS), and corresponding 95% confidence interval (95%CI). Results: Overall, for all metastatic ED-SCLC, receiving radiotherapy was associated with both improved OS and CSS. Generally speaking, radiotherapy for thoracic lesion and any metastatic sites could significantly improve the OS and CSS, except for brain metastasis. Before PS matching, radiotherapy significantly improved the survival of ED-SCLC patients with metastasis to brain (OS, HR = 0.71, with 95% CI = 0.61–0.83), however, the OS improvement became insignificant after PS matching (OS, HR = 0.91, with 95% CI = 0.74–1.12). For those M1a-SCLC patients without pleural effusion, radiotherapy, most likely to the primary site, also significantly improved the survival (P < 0.001). Furthermore, for those ED-SCLC patients with ≥ 2 metastatic sites, i.e., poly-metastatic ED-SCLC patients, radiation significantly improved the median OS from 6.0 months to 8.0 months (P = 0.015) and the median CSS from 7.0 months to 8.0 months (P = 0.020). Conclusions: The results suport radiotherapy in addition to chemotherapy might improve the survival of patients with metastatic ED-SCLC in a PS-matched patient cohort from the large SEER database. Although it should be adequately studied in phase III trials, it is prudent to select patients for radiotherapy in metastatic ED-SCLC. Legal entity responsible for the study: Dr. Zhenming Fu, Cancer Center, Renmin Hospital of Wuhan University, Wuhan, China Funding: National Science Foundation of China (NSFC) Disclosure: All authors have declared no conflicts of interest.