Evaluation of radiotherapy efficacy and prognostic analysis for solid and cystic brain metastases

Abstract

Purpose Brain metastases (BMs) are commonly categorized into cystic and solid. Despite advances in treatment modalities, the prognosis for patients with cystic and solid BMs following radiotherapy remains poorly understood. We use a retrospective design to elucidate the disparities in survival between these two patient groups undergoing radiotherapy and identify factors influencing overall survival (OS) of BMs in solid tumor. Methods This retrospective study encompasses 212 patients diagnosed with BMs. We meticulously analyzed the clinical characteristics, radiation therapy modalities, and risk factors influencing overall survival among these patients, categorized by BMs type, post-brain radiation therapy. Results A statistically significant difference in mOS was observed between the two cohorts (Solid vs. Cystic: 23.1 vs. 14.6 months). Subgroup analysis unveiled distinctions in mOS, particularly in patients with EGFR-mutant lung adenocarcinoma (Solid vs. Cystic: 23.1 vs. 6.43 months). The volume of BMs and the biological effective dose (BED) emerged as significantly prognostic factors for patients with cystic BMs. For patients with solid BMs, fraction dose, BED and the number of BMs were identified as independent prognostic factors for survival. Conclusion Brain radiotherapy shows superior survival benefits for lung cancer patients with solid BMs compared to those with cystic BMs, particularly in EGFR-mutant lung cancer. In particular, patients receiving BED ≥ 60Gy have a more favorable prognosis than those receiving BED < 60Gy, regardless of the type of BM (solid or cystic) in lung cancer.