New treatment strategy for craniopharyngioma using Gamma Knife radiosurgery - From long-term results of 100 consecutive cases

One hundred craniopharyngioma cases were treated by Gamma Knife and followed-up for a mean of 65.5 (6-148) months. Mean tumor diameter and volume were 18.8 mm and 3.8ml. The tumors were treated with a maximum dose of 21.SGy, a marginal dose of 11.5Gy, and a mean of 4.5 isocenters. Overall, the complete response rate was 19.4%, response rate 67.4%, control rate 79.6% and progression rate 20.4%. Analysis of complete response cases revealed age (adult), solid tumors less than 15.9 nun in diameter and fewer previous treatments to be good prognostic factors, along with a mean marginal dose of 12.1 Gy. Eighteen of 20 progression cases had cystic-mixed tumors and the cause of progression was cyst enlargement in 9, tumor regrowth in 8 and a new lesion in 3 cases. Among these factors, being an adult was a significantly favorable factor, while cystic and mixed tumor types were significant poor prognostic factors. Regarding the changes in neurological and pituitary-hypothalamic symptoms after Gamma Knife radiosurgery, overall improvement Was seen in 17 (18.7%), no change in 59 (64.8 %) and deterioration in 15 (16.5%). Three cases each had visual and endocrine deteriorations thought to represent side effects of Gamma Knife radiosurgery. Outcomes were excellent in 45, good in 23, fair in 4, poor in 3 and death in 16. A new treatment strategy has been proposed, in which small residual or recurrent tumors at the so-called 'R-site' (tumor origin) are targets for Gamma Knife radiosurgery, as an alternative to total removal. With this strategy, permanent cure can be expected without neuro-endocrine deficit. In conclusion, stereotactic Gamma Knife radiosurgery is safe and effective, with minimal side effects, as adjuvant or boost therapy for residual and/or recurrent craniopharyngiornas after surgical removal. Copyright (c) 2006 S. Karger AG, Basel.