The radiotherapy of cystic craniopharyngioma with intracystic installation of 90Y silicate colloid.

The authors describe the intracavital treatment with 90Y silicate colloid in 9 cases of cystic craniopharyngioma. The method has been applied since 1975 in the National Institute of Neurosurgery, Budapest. The intracavital treatment was only one among several applied treatment forms. In all patients a partial removal of the tumour has also been performed. The possibilities of evaluation of the effectiveness of the internal cyst irradiation are therefore limited. In most cases the intracavital treatment resulted in shrinkage of the cyst, or even was followed by its practical disappearence and the condition of the patients shows a decisive improvement. The growth of solid tumour parts is not influenced by this kind of treatment. Therefore the clinical improvement of the patient's condition depends also on the ratio between cyst and solid tumour volume. The optic nerve impairment did not improve in all cases. As a side-effect an oculomotor nerve paresis developed in several patients. Its possible explanations have been discussed, including lasting damage from tumour pressure.