Background. The treatment of primary and recurrent skull base meningiomas presents a formidable surgical problem.
Methods. Fifteen patients with primary and recurrent skull base meningiomas were treated by means of interstitial irradiation with iodine 125 ( I T ) seed implantation. The physical characteristics of lZ5I enabled the authors to administer a minimum tumor dose ranging from 100 to 500 Gy at a low dose rate of 0.05-0.25 Gy per hour.
Results. All 15 patients are alive at a median followup of 29 months. Of the 15 patients, 2 with calcification and 2 without calcification achieved only partial responses. The remaining 11 patients achieved a complete response. No early or late complications were observed.
Conclusions. From these data, the authors conclude that interstitial irradiation with '''I seeds is an effective, safe, and simple method in the treatment of both recurrent and primary skull base meningiomas. Cancer 1993; 71~3726-31.
Key words: skull base meningiomas, iodine 125 interstitial irradiation, low-dose-rate iodine 125 brachytherapy, nonsurgical management of meningiomas.
Meningiomas account for 13-18% of all primary intracranial tumors and approximately 25% of intraspinal tumors. In the latter group they are secondary to the schwannomas. They occur in patients at any age but are mainly neoplasms of adults, with most cases occurring in patients between 20 and 60 years of age, with a peak incidence at approximately 45 years of age. For menin-