Radt-12. Clinical Relevance of Radiation-Induced Cavernous Malformations

Abstract BACKGROUND Radiation-induced cavernous malformations (RICMs) are delayed complications of brain irradiation during childhood. The prevalence of cavernomas in the general population was found to be 0.5% in a large prospective study. However, the exact incidence of RICM in children and the mechanisms of the development of RICM remain largely unknown since the cumulative incidence of RICM is underreported. Recent systemic review revealed 113 children with RICM after treatment of brain tumors and leukemias. 67% were asymptomatic and 21% showed signs of hemorrhage. In this review, the average dose of radiation was 50Gy and the mean time to detection was 9.2 years. METHODS We conducted a retrospective review of RICM in children who underwent total body irradiation (TBI) for bone marrow transplant. Our study goals were to better understand the incidence and patterns of RICMs and to develop a risk stratification for monitoring. Between 9/2000-1/2023, 161 patients underwent TBI. Of 47 patients who had post-transplant brain MR imaging done, 15 patients had MRIs available for review. RESULTS Of 15 reviewed MRIs, 11 (73.3%) had RICMs identified. 6 cases had 5 small (3mm) RICMs. Most RICMs were in the frontal lobes. MRIs were obtained an average of 64 months from TBI. Radiation doses ranged from 200-2760cGy with an average of 1144cGy. There was 1 case of microhemorrhage due to RICM. None of our patients deceased as a result of their RICM. CONCLUSIONS Our cohort showed a high incidence (73.3%) of RICM despite low doses of radiation. Due to their typically small size and lack of clinical symptoms, RICM is often underreported. Although the outcome of cavernous malformation is favorable, it is important to understand the incidence and risk of adverse neurologic outcomes posed by RICMs. By performing regular surveillance, complications related to RICMs may be intervened with preventative procedures such as microsurgery.