Early Tumor Shrinkage as a Predictor of Favorable Treatment Outcomes in Patients With Extensive-Stage SCLC Who Received Programmed Cell Death-Ligand 1 Inhibitor Plus Platinum-Etoposide Chemotherapy: A Prospective Observational Study

In recent years, programmed cell death-ligand 1 (PD-L1) inhibitor plus platinum-etoposide chemotherapy was found to have favorable clinical outcomes in patients with extensive-stage SCLC (ES-SCLC). The usefulness of early tumor shrinkage (ETS) has been reported in various types of cancers. Nevertheless, there have been few reports evaluating ETS in ES-SCLC. Therefore, this study aimed to evaluate the role of ETS in the clinical outcomes of patients with ES-SCLC receiving chemoimmunotherapy.