Small cell lung cancer accounts for 15% to 20% of all primary bronchial lung cancers, and almost all SCLC patients are closely associated with smoking. Compared with non-small cell lung cancer, SCLC cells have biological characteristics such as poor differentiation, rapid proliferation, short ploidy time, high malignancy, early and extensive hematogenous metastasis. Disease staging is still the most important prognostic indicator for SCLC. The common clinical staging method for SCLC is the American Legion classification of limited and extensive stage, but nowadays it is often combined with the American Cancer Society’s TNM staging criteria for staging. The limited stage is defined as stage I and II SCLC in which the lesion is confined to one side of the chest, including contralateral mediastinal and ipsilateral supraclavicular lymph node metastases, and the lesion is able to be included within one radiotherapy treatment field. the extensive stage is defined as beyond one side of the chest, including lesions with contralateral hilar and supraclavicular lymph node metastases, malignant chest, pericardial effusion or hematogenous metastases, and also includes stage III and IV SCLC with multiple lesions in the same lung lobe or different lung lobes At present, chemotherapy and radiotherapy are still the main strategies for SCLC treatment, and surgery is only applicable to 2% to 5% of stage I patients. For patients with limited-stage SCLC, the goal of radical chemotherapy, radiotherapy or surgery is to achieve a cure, but most patients quickly relapse in situ or have distant metastases, with a 5-year survival rate of only 10%. Although thoracic radiotherapy and prophylactic whole brain irradiation have improved the clinical prognosis of SCLC in recent years, the improvement of survival for patients with extensive SCLC is extremely limited, despite the emergence of new drugs and the increasing remission rate of treatment. Through several revisions of the diagnostic and treatment guidelines in recent years, the comprehensive treatment of SCLC has become increasingly mature and reasonable.