Prospective Observational Study on ES-SCLC

This is an observational cohort study. There is no intervention assigned by the study protocol. Treatment strategies (including but not limited to chemotherapy, immunotherapy, radiotherapy, and local interventional therapy) are determined solely by the treating physician based on clinical practice guidelines and individual patient circumstances.Patients will receive real-world anti-tumor treatments as prescribed by their physicians. Common treatments for extensive-stage small cell lung cancer (ES-SCLC) may include platinum-etoposide chemotherapy, immune checkpoint inhibitors (such as anti-PD-L1/PD-1 antibodies), radiotherapy, and other therapies per standard clinical practice. The study will observe and record these treatments and their outcomes.