Abstract: Lung cancer remains one of the most frequent causes of cancer death in worldwide.Most of patients with bronchogenic carcinoma will be diagnosed with Non-small Cell Lung Cancer(NSCLC).With the popularization of computed tomography(CT)screening,NSCLC are increasingly detected at an early stage(IA or IB).Surgical resection remains the standard treatment for patients with stage I NSCLC.But only 60% of them is operable.The conventional radiotherapy administering a total dose of 60~66Gy in 1.8 to 2.0Gy/fraction for early-stage NSCLC is considered reasonable nonsurgical therapy for patients who can not tolerate surgery,with poor local control rates and survival rates.The poor results with conventional radiotherapy have been attributed to doses that are too low to control the tumor.Many long-term follow-up research demonstrate that SBRT has become the standard treatment for patients with early-stage NSCLC who cannot be resected,even for those who can tolerate surgery.

Key words: Non-small Cell Lung Cancer, Early-stage, Stereotactic body radiotherapy