Study design and patients
ONCOLOGY, BRAIN METASTASIS, METASTASIS
This non-randomized clinical trial was approved by the ethics committee of Peking Union Medical College Hospital, and was registered with ClinicalTrials.gov (NCT04453930). All patients signed the informed consent before any procedure. The key inclusion criteria were patients aged 18 to 75 years old; pathologically or cytologically confirmed ES-SCLC; previously untreated (including radiotherapy, chemotherapy, vascular endothelial growth factor receptor [VEGFR] inhibitors and ICIs); with an Eastern Cooperative Oncology Group performance status (ECOG PS) score of 0-1. Patients with active brain metastasis or meningeal metastasis were excluded. Detailed inclusion and exclusion criteria were presented in the 