RADT-08. INCIDENCE AND RISK OF SYMPTOMATIC RADIATION NECROSIS FOLLOWING INTRACRANIAL BRACHYTHERAPY: A SYSTEMATIC REVIEW AND META-ANALYSIS

Abstract PURPOSE Brachytherapy, offering highly localized radiation delivery while minimizing exposure to surrounding tissues, has reemerged as a promising treatment modality for primary and secondary brain tumors. Despite its usefulness, a significant complication seen following brachytherapy is symptomatic radiation necrosis (SRN). This meta-analysis aimed to estimate the pooled incidence of SRN following intracranial brachytherapy and explore associations between clinical and technical variables and SRN risk. METHODS Following PRISMA guidelines, a comprehensive literature search (PubMed, Embase, Web of Science, and Cochrane Library) identified studies that reported rates of SRN following brachytherapy for brain tumors in human patients. A random effects generalized linear mixed model was used to pool SRN rates, with subgroup analyses based on clinical and technical variables. Study quality was assessed using NIH tools, and level of evidence was assigned according to Oxford criteria. RESULTS Eighty-three studies totaling 3,666 patients were included. The pooled incidence of SRN was 5.67% (95% CI: 3.84%–8.29%) with substantial heterogeneity (I² = 75.7%). Exclusion of lower-quality studies yielded a pooled incidence of 7.61% (95% CI: 6.46%–8.94%). Subgroup analyses by tumor type showed pooled SRN rates of 3.72% for low-grade gliomas, 8.44% for high-grade gliomas, 2.07% for brain metastases, and 8.98% for meningiomas. Isotope subgroup analysis demonstrated SRN rates of 5.83% for Iodine-125, 7.61% for Iridium-192, and 2.07% for Cesium-131. No statistically significant differences were observed between tumor types, isotopes, implantation methods, dose rates, or prior radiation status. CONCLUSION SRN presents as a complication of intracranial brachytherapy in approximately 5.7% of patients, a rate comparable to other focal radiation therapies. Despite not showing statistical significance, trends suggest that tumor type and isotope selection may influence RN risk. Brachytherapy remains a safe treatment option for appropriately selected patients, with future prospective studies needed to optimize strategies for minimizing and managing RN.