Patients with extensive-stage small cell lung cancer achieving CR or PR after chemotherapy and thoracic radiation therapy were randomly divided into observation group and prophylactic cranial irradiation (PCI) group to evaluate the effect of PCI on survival after radiation therapy for thoracic lesions. To preliminarily analyze the clinical characteristics of patients who would benefit from thoracic radiation therapy plus PCI. To explore the optimal treatment modality after chemotherapy + thoracic radiation therapy in patients with extensive-stage SCLC.
prophylactic cranial irradiation （PCI）was verified to decrease the brain metastases rates and improve the overall survival（OS）for patients with limited stage small cell lung cancer.We hypothesis that patients with extensive-stage small cell lung cancer after chemotherapy and thoracic radiation can also benefit from PCI.