[Stereotactic interstitial radiosurgery and percutaneous radiotherapy in treatment of cerebral metastases].

The efficacy of interstitial radiosurgery as an alternative or adjuvant to radiotherapy or surgery of cerebral metastases remains unclear. In a retrospective study (1982-1991) we compared 4 therapeutic regimes for cerebral metastases. The first group (n = 38) was treated with interstitial radiosurgery (Iodine-125) with a tumor dose of 60 Gy in combination with percutaneous radiotherapy with 40 Gy. The second group was treated by interstitial radiosurgery alone (n = 22) (tumor dose: 60 Gy). The third group was treated with percutaneous radiotherapy alone with a total dose of 40 Gy (n = 49). The fourth group (n = 21) consisted of recurrent cerebral metastases which were treated by interstitial radiosurgery alone (tumor dose: 60 Gy). Interstitial radiosurgery was performed in cases of circumscribed mostly solitary metastases < or = 5 cm in diameter. Medium survival was 17 months after interstitial radiosurgery in combination with radiotherapy, 12 months after radiosurgery alone and 7.7 months after percutaneous radiotherapy. The medium survival of recurrent metastases after interstitial radiosurgery was 6 months. Prognostically favourable for the outcome following radiosurgery were a Karnofsky Score > or = 70, a solitary metastasis, absence of disseminated disease and a longer time interval between diagnosis of the primary and diagnosis of the cerebral metastases. Interstitial radiosurgery + percutaneous radiotherapy was not superior to interstitial radiosurgery alone in the multivariate analysis. No patient died from a locally treated metastasis. Percutaneous radiotherapy was the treatment of choice for multiple or non-circumscribed cerebral metastases. Our results show that for solitary metastases stereotactic interstitial radiosurgery is a beneficial minimally invasive method.