Real-world Experience of Embolization for Intracranial Tumors in Japan: Analysis of 2,756 Cases from Japanese Registry of NeuroEndovascular Therapy 4

Embolization of intracranial tumors is predominantly performed in Japan, primarily before neurosurgical resection. The Japanese Registry of NeuroEndovascular Therapy (JR-NET) Study Group, established in 2005, aims to clarify the factors influencing the outcomes of neuroendovascular treatment. Japanese Registry of NeuroEndovascular Therapy 4 is a nationwide, multicenter retrospective observational study that evaluates real-world data on intracranial tumor embolization in Japan. Japanese Registry of NeuroEndovascular Therapy 4 is based on data collected from 166 neurosurgical centers in Japan between January 2015 and December 2019. Of 63,230 patients, 2,664 (4.2%) with intracranial tumors underwent embolization. The primary endpoint was the proportion of patients with a modified Rankin scale (mRS) score of 0-2 at 30 days post-procedure. Secondary endpoints included procedure-related complications. Among the 2,664 patients, 61 records lacked sufficient data, leaving 2,603 patients (1,612 females, median age: 61 years [interquartile range 51-71]). The proportion of patients with mRS scores ≤2 at 30 days after the procedure was 86.9%. The overall incidence of procedure-related complications was 4.8%, with 1.8% hemorrhagic, 2.0% ischemic, and 1.0% classified as other complications. In the multivariate analysis, general anesthesia and embolization of vessels other than the external carotid artery were identified as risk factors for the development of complications. Meningioma cases had a complication rate of 4.3%, with major complications occurring in 3.5%. Hemangioblastoma cases had a 14.9% complication rate, with major complications at 9.9%. Japanese Registry of NeuroEndovascular Therapy 4 provides comprehensive real-world data on intracranial tumor embolization in Japan, identifying risk factors to inform and improve the safe practice of intracranial tumor embolization in neuroendovascular therapy.