Interstitial irradiation of cerebral gliomas in childhood by permanently implanted 125-iodine--preliminary results.

19 children with a deeply located cerebral glioma were treated with continuous interstitial irradiation (stereotactically implanted 125-iodine). The accumulated dose at the tumor surface ranged in the low grade glioma group (Group A) from 55 to 100 Gy and in the high grade glioma group (group B) from 50 to 65 Gy. Patients in group B additionally received a fractionated external beam irradiation (15-20 Gy boost dose). Tumor shrinkage as seen on CT-scans 6 months postoperatively could be achieved in 100% of patients with a low grade glioma. The response rate of 6 children with a high grade glioma was 83%. With a mean follow up of 57.0 months (group A) and 56.2 months (group B) respectively the estimated 4.5 year survival probability was 92% for low grade gliomas and 83% for grade III/grade IV lesions. Permanent interstitial irradiation offers the possibility of local tumor control with low risk of severe side effects. The survival rates are promising and comparable with results of other study groups. For gliomas grade I and grade II a dose reduction may be feasible.