Incidence: Small cell lung cancer accounts for about 15-20% of lung cancer as a whole. Because of its high malignancy, it is prone to hematogenous metastasis, and most of them are already in extensive stage when diagnosed. Although chemotherapy is sensitive, it is easy to develop drug resistance, and it is difficult to treat after drug resistance. Diagnostic methods: pathological or cytological diagnosis can clarify the diagnosis Staging tests: the purpose is to understand whether the patient has distant metastasis and guide the treatment Examination contents: cranial MRI (enhancement), whole-body bone scan, ultrasound of neck and supraclavicular lymph nodes, abdominal ultrasound, chest enhancement CT. whole-body PET-CT examination can be used as screening, but it needs to be combined with cranial MRI, and some PET hypermetabolic lesions need Other tests should be performed to help clarify the nature of the disease. The treatment principle: localized stage: treatment is based on radiotherapy synchronization or sequential treatment, with an efficiency of 70-90% extensive stage: systemic chemotherapy is the main treatment, with an efficiency of 60-70% with EP regimen. According to the patient’s symptoms, partial metastases can be combined with local treatment to control symptoms. Post-treatment follow-up: follow-up every 3-4 months for 1-2 years after treatment, every 6 months for the 3rd-5th years, and once a year after 5 years. The follow-up includes: hematological examination, physical examination, enhanced CT of the chest and, if necessary, cranial MRI and bone scan.