Multicenter, Phase II Randomized Controlled Study of Adebrelimab Combined With Chemotherapy and Concurrent Low-Dose Radiotherapy (LDRT) for the Treatment of Extensive-Stage Small Cell Lung Cancer (SCLC)

Inclusion Criteria: * Participants aged 18 to 75 years, regardless of gender; * ECOG Performance Status (PS) score of 0-1; * Expected survival duration of no less than 8 weeks; * Histologically or cytologically confirmed extensive small cell lung cancer (according to the VALG staging system); * Subjects must not have received systemic therapy or radical radiotherapy for extensive SCLC prior to enrollment. Exclusion Criteria: * Tissue classifications of mixed small cell lung cancer and non-small cell lung cancer; * Patients who have undergone major surgical procedures within 28 days prior to the initial administration of the study drug, or those planning to undergo major surgery during the study period (as determined by the investigator); * Receipt of live attenuated vaccines within 28 days before the first dose or planned for the duration of the study; * Participation in another clinical trial within 28 days preceding initial dosing, involving any experimental agents; * History of receiving chest radiotherapy or plans for intensive chest radiotherapy prior to systemic therapy; * Any previous T-cell co-stimulation or immune checkpoint therapies administered; * Documented history of allogeneic organ transplantation or allogeneic hematopoietic stem cell transplantation.\"