Cumulative incidence of radiation-induced cavernomas in long-term survivors of medulloblastoma

Object. The goal of this study was to determine the incidence of radiation-induced cavernomas in children treated for medulloblastoma. Methods. A retrospective chart and film review was performed for all patients treated for medulloblastoma at the Insitute for Neurology and Neurosurgery/Beth Israel Medical Center between August 1996 and the present. The clinical and radiographic histories of pediatric patients (ages 3-21 years at diagnosis) with a histologically confirmed diagnosis of medulloblastoma who received craniospinal radiation therapy were reviewed. Fifty-nine patients were identified, with a mean age at radiation treatment of 7.7 years and a mean follow-up time of 7.2 years. The dose to the craniospinal axis was 24 Gy (31 patients) or 36 Gy (28 patients). The radiation energy in the craniospinal axis was provided by photons in 55 patients and protons in four. All patients received a posterior fossa boost of 54 Gy (46 patients) or 72 Gy (13 patients). Twenty-six lesions developed in 18 patients (31%) during the observation period. The cumulative incidence of lesion development was 5.6, 14, and 43%, at 3, 5, and 10 years, respectively. The sites of occurrence were cerebral (20 cases) and cerebellar (six cases). There was no significant correlation between age at diagnosis, sex, craniospinal radiation dose or energy source, and lesion development. Only one patient required surgical intervention for a symptomatic hemorrhagic lesion in the frontal lobe. Histological analysis in this case was consistent with cavernoma. Conclusions. Cavernomas are common after cranial irradiation in children, and their incidence increases over time. Most of these lesions follow a benign course and do not require intervention.