Low-dose Radiotherapy Combined With Durvalumab, Chemotherapy(EP) in the Treatment of ES-SCLC

Inclusion Criteria: * At the time of screening, male or female participants were ≥18 years old. * Before carrying out any research program related procedures (including screening evaluation), obtain written informed consent and any locally required authorization from the participant or his legal representative. * Extensive-stage disease confirmed by histology or cytology (American Joint Committee on Cancer (8th edition) stage IV SCLC \[any T, any N and M1a/b/c\]), or due to multiple lung nodules with a wide range Or the size of the tumor/nodule is too large to be included in a tolerable radiotherapy plan for stage T3-4 disease. Participants with brain metastases must be asymptomatic or stable with steroids and anticonvulsants for at least 1 month before study treatment. Participants with suspected brain metastases during screening should undergo brain CT/MRI before enrollment in the study. * The participant must be considered suitable for platinum-based chemotherapy as the first-line treatment for extensive-stage small cell lung cancer. Chemotherapy must include either cisplatin or carboplatin, combined with etoposide. * The participant must be considered suitable for thoracic radiotherapy as the first-line treatment for extensive-stage small cell lung cancer. * Life expectancy on the first day of study treatment was ≥12 weeks. * At the time of enrollment, the World Health Organization (WHO)/Eastern Cooperative Oncology Group (ECOG) physical status score was 0 or 1. * Weig…