INTERSTITIAL I-125 RADIOSURGERY FOR CEREBRAL METASTASES

The current study evaluates the efficacy of interstitial 125-iodine ra diosurgery (brachytherapy) in 93 patients with circumscribed, spherica l, mostly solitary metastases. In all patients the histological diagno sis was established by stereotactic biopsy. The treatment results of t hree therapeutic regimens have been examined retrospectively: Group A (38 patients) had interstitial radiosurgery with a reference tumour do se of 60 Gy in combination with percutaneous radiotherapy (40 Gy). Gro up B (34 patients) was treated by interstitial radiosurgery alone (ref erence dose 60 Gy). Group C (21 patients with recurrent metastases aft er previous radiotherapy/surgery) was treated by interstitial radiosur gery alone (reference dose 60 Gy). Median survival after interstitial radiosurgery was 17? months in group A, 15 months in group B, 6 months in group C. Favourable prognostic factors were a Karnofsky performanc e rating greater than or equal to 70, solitary metastasis, absence of disseminated disease, and a time interval > 1 year between diagnosis o f the primary tumour and diagnosis of the cerebral metastases. Interst itial radiosurgery plus percutaneous radiotherapy did not prove to be superior to interstitial radiosurgery alone. No patient died of a loca lly irradiated metastasis. We conclude that interstitial radiosurgery achieves control of the growth of solitary spherical cerebral metastas es in any location without radiation toxicity.