Permanent Iodine-125 Implants in the Treatment of Low-Grade Gliomas

We report a retrospective study on the use of the permanent iodine-125 (125I) implants in the management of low-grade gliomas. From July 1988 to July 1997, 16 patients with low-grade gliomas underwent permanent 125I implants in the management of their lesions. There were 7 males and 9 females ranging in age from 4 to 48 years (mean 19). The location was in the cerebral hemisphere in 7 patients, brainstem in 5 patients and thalamus/basal ganglia in 4 patients. Prior to brachytherapy, 9 patients underwent surgical resection and 7 patients underwent stereotactic biopsy procedures. Fourteen patients were treated as part of the initial management and 2 were recurrent. The histological diagnosis was: 9 WHO grade II astrocytomas, 3 oligodendrogliomas, 2 gemistocytic astrocytomas, 1 pilocytic astrocytoma, and 1 ependymoma. The tumor volume ranged from 0.7 to 33.4 cc (mean 8.4). Stereotactic treatment planning was used to encompass the contrast-enhancing rim of the tumor visualized by computerized tomography with an initial dose rate of 0.05 Gy/hour with 125I. The total activity ranged from 0.8 to 20.5 mCi. With a median follow-up period of 35 months (range, 4–105 months), the 2- and 5-year survival rates were 93.7% and 87.5%, respectively. Three patients underwent reoperation after implants, two of three had recurrent disease, and one had radiation necrosis. Permanent 125I implants appear to be safe and effective as a part of the multimodality management of low-grade gliomas.
Source: Journal of Radiosurgery - Category: Radiology Source Type: research