Cerebral glucose metabolism in long-term survivors of childhood primary brain tumors treated with surgery and radiotherapy.

Delayed structural cerebral sequelae has been reported following cranial radiation therapy (CRT) to children with primary brain tumors, but little is known about potential functional changes. Twenty-four patients were included, diagnosed and treated at a median age of 11 years, and examined after a median recurrence free survival of 16 years by MRI and Positron Emission Tomography using the glucose analog 2-18F-fluoro-2-deoxy-D-glucose (18FDG). Three patients were not analyzed further due to diffuse cerebral atrophy, which might be related to previous hydrocephalus. Twenty-one patients were evaluable and regional cerebral metabolic rate for glucose (rCMRglc) was estimated in nontumoral brain regions in 12 patients treated with surgery alone and 9 patients treated with both surgery and CRT. Furthermore 10 normal controls matched for age at examination were included. Patients treated with both surgery and CRT had a general decreased rCMRglc compared to normal controls and patients treated with surgery alone, significantly (p < 0.05) in 5 of 11 regions of interest. No difference was found in rCMRglc between normal controls and patients treated with surgery alone. We conclude that there is a general reduction in rCMRglc in long-term recurrence free survivors of childhood primary brain tumors treated with CRT in high doses (44-56 Gy).