Radiotherapy-related intracranial aneurysm: case presentation of a 17-year male and a meta-analysis based on individual patient data.

PURPOSE: The aim of this study was to investigate the incidence, clinical profiles, latency, and outcomes of radiotherapy (RT)-related intracranial aneurysms, rare but often fatal complications of cranial irradiation. METHODS: We reviewed all published individual patient data regardless of language, using survival analysis to make statistical inferences. RESULTS: We examined a total of 58 patients with RT-related intracranial aneurysms, including one unpublished case presented here, of whom 74.1 % presented with rupture. In the study, 29.3 % were younger than 18 years. The mean age at which patients received the first course of RT was 34.8 ± 22.8 years old. The mean latency between initiating RT and presenting with aneurysm was 10.4 ± 8.5 years. Rapid death ensured in 24 % shortly after presentation. The only significant predictor of death was rupture. In those with a single aneurysm, 43.1 % were located at the internal carotid artery, while 15.5 % of patients had multiple aneurysms. A male-to-female ratio of 1.87, 0.5, and 1.32 was found in patients younger than age 52, 52 years of age or older, and all 58 patients, respectively. Older age when receiving RT and presentation with ruptured aneurysm were significantly associated with shorter latency. CONCLUSIONS: RT-related intracranial aneurysms presented differently from classical ones based on age, sex, site, multiplicity, and type. Sex ratios differed with age. The younger age group showed a longer latency of occurrence of an aneurysm. Older patients and those who develop ruptured aneurysms presented earlier. Since rupture may affect outcome, early detection of aneurysms before rupture may save lives.