Combination of immunotherapy and whole-brain radiotherapy on prognosis of patients with multiple brain metastases: A retrospective cohort study

Brain metastases (BMs) usually occur in the advanced stage of cancers with a poor prognosis. This study aimed to compare the clinical efficacy and effects on cognitive function of immunotherapy combined with whole brain radiotherapy (WBRT) and immunotherapy combined with WBRT plus sequential integrated boost (SEB) in the treatment of multiple BMs. A total of 57 patients diagnosed with BMs were included in Kezhou People's Hospital Affiliated to Nanjing Medical University between 2021 and 2023. Patients were allocated into the WBRT group (<i>n</i> = 27) and the WBRT + SEB group (<i>n</i> = 30) based on whether to receive a boost. The WBRT + SEB group showed a higher complete response rate and objective response rate compared to the WBRT group (26.7 vs 14.8%, 90.0 vs 66.7%) (all <i>P</i> < 0.05). The two groups had a median overall survival (OS) time of 11.2 months (95% confidence interval [CI]: 9.3-13.1) and 9.4 months (95% CI: 6.2-12.6), respectively, with no statistically significant difference (<i>P</i> = 0.176). There was no difference in the levels of mini-mental state examination score at 1, 3, and 6 months, as well as the risk of adverse events, after WBRT between the two groups. In conclusion, SEB may improve the remission rate of lesions but not prolong the OS time. The boost would neither increase serious side effects nor would it aggravate cognitive impairment caused by WBRT.