External irradiation followed by an interstitial high activity iodine-125 implant "boost" in the initial treatment of malignant gliomas: NCOG study 6G-82-2.

Between January 1982 and January 1990, 107 patients with unifocal, circumscribed malignant gliomas participated in a non-randomized trial testing brachytherapy in their initial treatment. Focal external irradiation (6000 cGy) was combined with an implant of high-activity iodine-125 (5000-6000 cGy) and six courses of procarbazine, lomustine, and vincristine. Of the 101 evaluable patients, 63 received implants. Of these, 29 had non-glioblastoma anaplastic gliomas, and 34 had glioblastoma multiforme. The other 38 did not receive implants, in most cases because radiation therapy failed to reduce the size of the tumor. The median survival was 165 weeks for all evaluable patients with non-glioblastoma anaplastic gliomas, 157 weeks for those with implants, 67 weeks for all evaluable glioblastoma patients, and 88 weeks for those with implants. Of the glioblastoma patients with implants, nine were alive after 2 years, and three were alive after 3 years. In each of the groups, nearly half the patients underwent reoperation for clinical deterioration, increasing steroid dependency, and increasing mass effect at the implantation site after 46.1 weeks (median) for glioblastoma multiforme and 41.3 weeks for non-glioblastoma patients. Karnofsky Performance Scores showed only a small decline in performance after brachytherapy. Patients receiving implants for non-glioblastoma anaplastic gliomas had a mean Karnofsky Performance Score of 91% (range 90-100%) after 1 month and 78% (range 60-100%) 30 months after brachytherapy. Those treated for glioblastoma multiforme had a mean Karnofsky Performance Score of 86% (range 60-100%) at 1 month and 75% (range 60-100%) at 24 months. The quality of life of treated patients appears to be satisfactory. On the basis of comparisons with previous studies, we conclude that a brachytherapy "boost" after external irradiation may be valuable for some patients with glioblastoma multiforme but not for those with non-glioblastoma anaplastic gliomas.