Data collection
SCLC, death, primary tumors
PRIMARY TUMORS, SCLC, MAY, TUMOR PROGRESSION, ONCOLOGY
A total of 612 patients pathologically diagnosed with SCLC from the First Hospital of China Medical University between March 2008 and August 2021 were included. Inclusion criteria were as follows: availability of complete patient records; no previous tumor‐related treatment; patients who received at least two cycles of standard first‐line platinum‐based doublet chemotherapy and at least once standardized evaluation of efficacy; no previous history of other primary tumors except for SCLC; Eastern Cooperative Oncology Group (ECOG) performance score 0–1. There were only 22 patients receiving PD‐L1 inhibitors in combination with platinum‐based chemotherapy in the first‐line treatment. The last follow‐up date was May 1, 2022. OS was defined as the interval from the date of initial diagnosis to death. OS time for patients who lost to follow‐up or were alive as of last follow‐up was equal to the date of last follow‐up. PFS was the time interval from original diagnosis to documented tumor progression or death due to any cause.