Radiation-Induced Intracranial Aneurysm After Cranial Radiation Therapy: Hemodynamic Considerations in a Long-Term...

Long-term survival after glioblastoma (GB) remains uncommon; however, advances in genomic research and contemporary multimodal therapy have increased the number of long-term survivors. In these patients, late effects of cranial radiation therapy may accumulate over time, affecting cognitive and endocrine function and increasing the risk of cerebrovascular disorders and secondary malignancies. We report a long-term GB survivor who developed multiple late radiation-related complications, including radiation-induced intracranial aneurysm (RIA). During the clinical course of this case, serial imaging demonstrated that hemodynamic stress secondary to proximal large-artery stenosis/occlusion contributed to aneurysm formation. This observation suggests that cerebrovascular risk after cranial irradiation cannot be assessed solely on the basis of radiation dose distribution and that hemodynamic stress may play a contributory role in RIA development. This case highlights 2 important clinical implications. First, late radiation-related complications may accumulate in the same long-term GB survivor and become critical determinants of outcome. Second, cerebrovascular risk cannot be assessed based on radiation dose distribution alone, and the effects of hemodynamic stress should be considered. With advances in genomics and contemporary care increasing the number of long-term survivors, the incidence of postradiation therapy complications is likely to rise. To reduce preventable morbidity, surveillance should extend beyond tumor control to include longitudinal vascular assessment, with explicit attention to hemodynamic warning signs, such as new arterial stenoses, evolving collateral pathways, and de novo or enlarging aneurysms.