Objective: To compare the local/regional failure pattern and overall survival (OS) between limited-stage SCLC patients who received different target volumes of thoracic radiotherapy (TRT)after induction chemotherapy.Methods: Patients diagnosed as limited-stage (AJCC/UICC T 1-4N0-3M0) SCLC received two cycles of etoposide and cisplatin(EP) and were randomly assigned to receive TRT to either the post-induction chemotherapy tumor extent (study arm) or preinduction chemotherapy tumor extent (control arm).Elective nodal irradiation was omitted in both arms, that is, clinical target volume-nodal included only initially involved nodal regions.TRT dosage of 45 Gy/30 Fx/19 d was administered concurrently with the third cycle of EP regimen.An additional three cycles of EP consolidation were administered.Prophylactic cranial irradiation was administered to patients who achieved complete or partial remission.