Dose-dependent cerebrovascular impact of pediatric brain radiotherapy revealed by advanced MRI: the AVARTHEC study

To describe the clinical, imaging, and dose characteristics of cerebral vascular disease (CVD) in childhood cancer survivors (CCS) after brain tumour irradiation, to assess prevalence by tumour type, and to evaluate the impact on quality of life (QoL).

A multicentre prospective study of brain tumour patients treated with radiotherapy (RT) between 1990 and 2002. We analysed clinical outcome, quality of life, sociodemographic information, RT dose and MR imaging with angio-MRI to investigate microbleeds and cavernomas.

163 patients were evaluated. The median age at RT was 9.2 years (1.3-18.9) and the median age at inclusion was 24.0 years (12-35), the median interval between RT and inclusion being 15 years. The most common primary tumours were medulloblastomas (40.5%), astrocytic and glial tumours (19%), germinomas (15%) and ependymomas (11%). A total of 210 abnormalities were diagnosed in 131 patients (80%), predominantly cavernomas (68.5%) and microbleeds (21%). Doses administered to vascular abnormalities could be evaluated in 71 patients. Median D mean radiation doses were 40.25 Gy for cavernomas, 39.5 Gy for microbleeds and 39.5 Gy for arterial stenoses. Six among the 8 aspects of health for assessment of quality of life were unchanged before and after MRI. Patients expressed a high level of satisfaction with the information given.

After a median follow-up of 15 years, 80% of CCS developed cerebral abnormalities, mainly in small vessels exposed to a median D mean dose of 40 Gy. The prevalence ranged from 92.4% in medulloblastoma to 50.0% in craniopharyngioma. Guidelines are needed for the delineation of organs at risk, follow-up and screening of cerebrovascular abnormalities using dedicated MRI sequences.