As stereotactic radiotherapy (SBRT) has been widely used in clinical practice at present, the aim of this study is to evaluate the efficacy and safety of stereotactic body radiation therapy compared with intensity modulated radiation therapy (IMRT) concurrently with EP regimen(cisplatin plus etoposide) in treating patients with limited-stage small cell lung cancer

Inclusion Criteria:

• Histologic or cytologic diagnosis of SCLC
• limited-stage disease is defined as disease confined to the ipsilateral hemithorax, which can be safely encompassed within a radiation field
• No prior chemotherapy, or radiotherapy
• Performance status of 0, 1, 2 on the ECOG criteria.
• At least one unidimensional measurable lesion meeting Response Evaluation Criteria in Solid Tumors (RECIST. 2000).
• Adequate hematologic (neutrophil count >= 1,500/uL, platelets >= 100,000/uL), hepatic (transaminase =< upper normal limit(UNL)x2.5, bilirubin level =< UNLx1.5), and renal (creatinine =< UNL) function
• If female: childbearing potential either terminated by surgery, radiation, or menopause, or attenuated by use of an approved contraceptive method (intrauterine device [IUD], birth control pills, or barrier device) during and for 3 months after trial. If male, use of an approved contraceptive method during the study and 3 months afterwards. Females with childbearing potential must have a urine negative HCG test within 7 days prior to the study enrollment.

Exclusion Criteria:

• Non small cell lung cancer and carcinoid
• Supraclavicular lymphadenopathy
• Inability to comply with protocol or study procedures.
• Moderate and severe ventilation dysfunction
• Medically uncontrolled serious heart, lung, neurological, psychological, metabolic disease
• Second primary malignancy that is clinically detectable at the time of consideration for study enrollment.
• Pregnant or breast-feeding.
• Enrollment in other study within 30 days