Comparing simultaneous integrated boost whole-brain radiotherapy and local irradiation for brain metastases in lung cancer: A retrospective analysis.

Background: This study aimed to evaluate the differences between simultaneous integrated boost whole-brain radiotherapy (SIB-WBRT) and brain metastases local irradiation efficacy, and determine predictors of outcomes for lung cancer brain metastases patients in therapy. Methods: This retrospective analysis evaluated patients with brain metastases treated with SIB-WBRT (whole brain at 40 Gy/20 fractions, tumor boosted to 56-60 Gy/20 fractions) and localized irradiation (prescribed doses ranging from 20-60 Gy over 2-25 fractions, typically administered as 30 Gy/5 fractions, with a biologically effective dose [BED] of 28-100.8 Gy) at PUMCH between September 2015 and December 2021. The primary outcome was intracranial progression-free survival (iPFS), with secondary outcomes encompassing overall survival (OS), development of new intracranial lesions, and tumor control. Propensity score matching was employed to compare the two retrospective groups. Survival curves for iPFS, OS, new intracranial lesions, and tumor control were generated and estimated using the Kaplan-Meier approach. Cox proportional hazards modeling was applied to examine the relationships between pertinent variables and clinical outcomes. Results: After Propensity score matching, 59 patients were enrolled in each group (SIB-WBRT and local irradiation), with a total of 118 patients included in the analysis. No significant difference was observed between the 2 groups in iPFS (HR = 0.8, 95%CI: 0.4-1.3, P = 0.288), OS (HR = 1.1, 95%CI: 0.7-1.8, P = 0.653), or incidence of intracranial new lesions (HR = 0.6, 95%CI: 0.4-1.2, P = 0.144). However, a statistically significant difference was noted in local control time between the groups, with local irradiation brain metastases being superior (HR = 0.4, 95% CI: 0.2-0.8, P = 0.005). Tumor volume and other factors were related to local control. Conclusion: Compared to local irradiation, SIB-WBRT did not significantly improve iPFS in patients with brain metastases. Compared to SIB-WBRT, local irradiation improved local control. Tumor volume and other factors may be associated with local control.