Brain injury after cranial radiotherapy combined with immunotherapy for brain metastases in lung cancer: a retrospective study.

To explore whether immune checkpoint inhibitors (ICIs) increase the incidence of radiation-induced brain injury in lung cancer patients with brain metastases. According to whether they received ICIs within 6 months before and after cranial radiotherapy (CRT), all patients were divided into two groups: ICIs + CRT group and CRT + non-ICIs group. The incidence of radiation necrosis (RN) in the CRT + ICIs group was 14.3%, while that in the CRT + non-ICIs group was 5.8% (p = 0.090). If ICIs were used within 3 months of CRT, there was statistical significance. A maximum diameter of brain metastasis >3.3 cm and cumulative radiation dose of metastatic lesions >75.7 Gy were risk factors for RN. ICIs could increase the risk of RN, especially when used within 3 months of CRT.