Long-term results and late complications after intracavitary yttrium-90 colloid irradiation of recurrent cystic craniopharyngiomas.

OBJECTIVE: Data were analyzed to assess the value of stereotactically applied intracystic colloidal yttrium-90 (YTx) for the treatment of recurrent cystic craniopharyngiomas during a 30-year period. METHODS: This article compares data from 73 YTx procedures in 60 patients between 1975 and 2006. The cumulative beta dose aimed at the inner surface of the cyst wall was 300 Gy. RESULTS: After YTx, the initial cyst volumes decreased an average of 79%. In 47, the reduction was more than 80%; in 27 of them, the cyst disappeared completely within 1 year. The mean survival after YTx was 9.4 years (range, 0.7-30 yr). Actuarial survival rates at 5, 10, 15, 20, 25, and 30 years were 81, 61, 45, 18, 2, and 0%, respectively. Late complications of YTx were related to the anatomic localization of the cyst, either presellar and retrosellar, e.g., a presellar (prechiasmatic/suprasellar) localization caused neuro-ophthalmological complications in 5.8% and internal carotid artery injury in 1.6%. The treatment of retrosellar (retrochiasmatic, suprasellar) tumors occasionally induced hypothalamic and/or pontomesencephalothalamic damage obviously by untoward radiation to the so-called perforating arteries. This occurred in 3.2% of these latter patients. CONCLUSION: Despite sporadic complications, intracavitary YTx irradiation is a valuable treatment alternative for craniopharyngioma cysts, sometimes as part of a multimodality management in these tumors, especially in precarious surgical cases.

Stereotactic intracavitary irradiation of cystic craniopharyngiomas with yttrium-90 isotope.

The authors analyzed data from nearly 30-year follow-up period to assess the value of intracavitary irradiation with stereotactically implanted beta-emitting radioisotope yttrium- 90 (90Y) silicate colloid for the treatment of cystic craniopharyngiomas. Seventy-three cysts in 60 patients were selected for retrospective analysis. The cumulative dose aimed at the inner surface of the cyst wall was 300 Gy. An average of 79% (mean 88.3%) shrinkage of the initial cyst volume was observed. In 47 cysts, the reduction was more than 80%, and the cyst disappeared totally in 29 out of those 47 cases, usually within a year. Mean survival duration after intracavitary irradiation was 9.4 years. Neuroophthalmological prognosis was only favorable when the optic disc was normal or nearly normal at the time of the treatment. In the presence of preexisting optic atrophy, visual damage proved to be irreversible. The long-term results support the view that intracavitary 90Y irradiation is a noninvasive and effective method for the treatment of craniopharyngioma cysts. Because of the mean penetration pathway of beta irradiation is 3.6mm in the soft tissues (maximum 11 mm) it cannot influence the solid part of the tumor; therefore, the best result can be expected in solitary cysts.