Anlotinib In Combination With PD-1/L1 Inhibitor As Sequential Therapy of Thoracic Radiotherapy After Induction Chemotherapy For Extensive-Stage Small Cell Lung Cancer:A Single Arm Study

Inclusion Criteria: 1. The subjects volunteered to join the study and signed the informed consent form. They had good compliance and cooperated with the follow-up; 2. Patients between 18-75 years old; 3. Extensive small cell lung cancer confirmed by histopathology (according to Veterans Administration lung study group, Valg stage) and did not progress after 4-6 cycles (21 days as a cycle) of first-line standard chemotherapy platinum combined with etoposide \[complete remission (CR), partial remission (PR) or stable (SD) according to recist1.1 standard\]; 4. The time interval between the first TRT and the end of the last chemotherapy should be less than or equal to 6 weeks; 5. The life expectancy shall be at least 3 months; 6. ECoG score: 0-1 Exclusion Criteria: 1. Small cell lung cancer patients with other pathological types of tumor species; 2. Patients with pathological fracture in bone metastasis of small cell lung cancer; 3. Patients with central nervous system metastasis; 4. Patients who have received chest radiotherapy before; 5. Patients who have used vasotargeted drugs (such as bevacizumab, sunitinib, etc.) including enrotinib and immunosuppressive agents before; 6. Imaging (CT or MRI) showed that the distance between the tumor focus and the large blood vessel was less than or equal to 5 mm, or there was a central tumor invading the local large blood vessel, or there was an obvious cavitary or necrotic tumor in the lung;