yttrium-silicate and Craniopharyngioma

Radiosurgery, using 90Y injected directly into the cavity of cystic craniopharyngiomas produces remarkable reduction of tumour size and diminishes cyst fluid production. The authors have studied the histology of biopsy and autopsy material obtained from seven patients presented with cystic craniopharyngiomas. Histological examination was carried out before and after 90Y silicate implantation. As an effect of 90Y irradiation, histology of samples taken from the cyst wall revealed that the lining epithelial cell layer became destroyed and the cyst wall shrunk. Large amount of collagen fibres with focal hyaline degeneration was present. Proliferation of intimal cells and subendothelial connective tissue narrowing small vessel lumina also occurred. Considering that fibrotic tissue is more susceptible to shrink, the fibrosis induced by irradiation together with destruction of the squamous epithelium and vascular changes, might explain the reduction of the cyst volume and diminished fluid secretion after 90Y treatment.

Topics: Brachytherapy; Combined Modality Therapy; Craniopharyngioma; Cysts; Humans; Hyalin; Pituitary Neoplasms; Silicates; Silicic Acid; Silicon Dioxide; Yttrium; Yttrium Radioisotopes

Fourteen children and 3 adults with cystic craniopharyngiomas were treated with intracavitary 90Y, by the procedure described by Backlund. Their ages ranged from 2 to 65 years and postoperative follow-up ranged from 6 to 40 months. Leksell's stereotactic technique was employed to determine coordinates by CAT. Cyst volume was quantified both geometrically and isotopically with 99Tc, values differing by 7%. Dosimetry was determined by applying the formula developed by Loevinger et al., and 20,000 rads were administered throughout to the cystic wall. All 17 patients, except for 4 children, had previously received surgery, shunts or radiotherapy, alone or combined. In 4 cases, 90Y injection was the only treatment, while in 6, the cyst was evacuated at 10 days following radiocolloid injection. Skull and spinal column gamma chamber studies were carried out on all patients at 24, 48, and 72 hours post injection, but no isotope leakage could be detected. The patients returned to normal activities except one with multiple cysts who died. There were no changes in the endocrinologic profile. In one case, a decrease in visual acuity 18 months after treatment, improved following corticoid administration.. Though preliminary, these results are encouraging since it seems that the severe neuro-endocrinologic sequelae of open surgery may be avoided.

Topics: Adolescent; Aged; Brain Neoplasms; Child; Child, Preschool; Colloids; Craniopharyngioma; Female; Humans; Infant; Male; Middle Aged; Silicates; Silicic Acid; Silicon Dioxide; Stereotaxic Techniques; Yttrium; Yttrium Radioisotopes

20 patients suffering from cystic craniopharyngioma were treated with intracavitary irradiation on 25 occasions. The beta emitting radionuclide 90Y silicate colloid was instilled into the cyst or cystic part of the tumour. 17 patients on 22 occasions underwent follow-up CT and ophthalmological examinations 1 to 144 (average: 34) months after the intracavitary radioisotope therapy. An 23 occasions there was an average of 82 to 90% volume decrease of the craniopharyngioma cysts. On two occasions the volume has remained unchanged and the result of the 90Y therapy cannot be evaluated yet. The neuroophthalmological prognosis was good only when a relatively intact optic disc was seen; when the disc was atrophic the visual deterioration proved to be irreversible. Pathologically, it is the fibrotic tissue that is responsible for the shrinkage of the cyst.

Topics: Brain Neoplasms; Colloids; Craniopharyngioma; Female; Humans; Male; Silicates; Silicic Acid; Silicon Dioxide; Vision Disorders; Yttrium; Yttrium Radioisotopes

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.

Topics: Adolescent; Adult; Brachytherapy; Child; Combined Modality Therapy; Craniopharyngioma; Cysts; Female; Humans; Male; Neoplasm Recurrence, Local; Pituitary Neoplasms; Silicates; Tomography, X-Ray Computed; Yttrium; Yttrium Radioisotopes