Effects of radiation therapy for glioma in children, with special reference to brain atrophy

The authors report the effects of radiation therapy for glioma in 61 children. Subsequent to irradiation the patients received long-term follow-up, which included computed tomographic (CT) scanning. Brain atrophy (BA) was considered to have occurred if one focus of cortical or brainstem atrophy, and/or ventricular dilatation, was identified on follow-up CT but had not been present on CT scans obtained immediately after the completion of radiation therapy. In 20 cases BA could not be evaluated. Thus, BA was found in 10 of the 41 cases (24.4%) at 33 months after radiation therapy. The mean whole brain irradiation doses in the BA(+) and BA (-) groups were 50.6 Gy and 28.7 Gy, respectively (p<0.001). All patients irradiated with more than 60 Gy developed BA. On the other hand, those who received less than 30 Gy had no BA. BA was not detected in cases of local brain irradiation. The authors also discuss typical radiation necrosis and calcificatin. Two of 61 patients (3.3%) developed radiation necrosis about 20 months after radiation therapy. Six (9.8%) were found to have local calcification, limited to the radiation field, about 30 months after irradiation. (author)