Objective To investigate the efficacy and safety of thoracic radiotherapy (TR) and prophylactic cranial irradiation (PCI) in patients with extensive small cell lung cancer (SCLC) who show response to chemotherapy. Methods From July 2010 to March 2012, 30 patients with a pathological or cytological diagnosis of extensive SCLC who showed response to 4—6 cycles of chemotherapy with carboplatin plus etoposide or chemotherapy with cisplatin plus etoposide were included in the study. The median age of patients was 57 years (range, 40—71 years). All the patients received TR (50—60 Gy) and PCI (25 Gy). The short-term efficacy was assessed by RECIST 1.1, and the toxicities were evaluated according to CTCAE 3.0 and RTOG radiation morbidity scoring criteria. Results Twenty-nine of the 30 patients completed the TR and PCI. Of these patients, 13% showed complete remission, 27% showed partial remission, and 60% showed stable disease, and the disease control rate was 100%. Progression was seen in 16 patients after effective treatment, including 1 patients with locoregional failure (LRF) alone and 15 patients with distant failure (DF)(9 patients with DF alone and 6 patients with locoregional and distant metastases, 4 patients with brain metastasis). The follow-up rate was 100%. The 1-year LRF rate and DF rate were 24% and 51%, respectively. The 1-year overall survival rate and disease-free survival rate were 71% and 37%, respectively. The acute toxicities included grade ≥2 hematological toxicity and grade ≥2 radiation esophagitis, which occurred in 33% and 13% of all patients. Conclusions TR and PCI have good short-term efficacy and safety in extensive SCLC patients with response to chemotherapy and can reduceDOI:10.3760/cma.j.issn.1004-4221.2013.05.007基金项目:北京希望马拉松专项基金(N2010-8)作者单位:100021 北京协和医学院中国医学科学院肿瘤医院肿瘤研究所放疗科(张文珏、周宗玫、陈东福、梁军、冯勤付、张红星、王小震、惠周光、肖泽芬、吕纪马、王绿化),内科(李峻岭)通信作者:周宗玫,Email:zhouzongmei2013@163.combrain metastases and local recurrence. However, further study is needed with a larger sample.