Intracavitary brachytherapy of cystic craniopharyngiomas

Abstract

Visual function, endocrinological status, and radiological outcome are reported in 31 patients harboring a cystic craniopharyngioma, who underwent 35 intracavitary brachytherapy procedures with yttrium-90. In 26 of these patients intracavitary brachytherapy was the primary treatment. The follow-up period ranged from 2 to 80 months (41 +/- 22 months, mean +/- standard deviation). Five patients died from tumor-related causes. Endocrine recovery was modest. Prior to brachytherapy, visual acuity was diminished in 38 eyes and field defects were present in 46. Funduscopy before treatment revealed optic atrophy in 47% of the eyes. Visual acuity improved in 29% of the eyes studied, remained stable in 13%, and deteriorated in 58%. Visual field defects improved in 28% of the eyes studied, remained stable in 20%, and deteriorated in 52%. The possible causes for deterioration in visual function are discussed. Complete resolution of 10 cysts was noted. In 12 patients the size of the cyst decreased; however, in three of these patients new cyst formation took place. The cyst size stabilized in six cases and increased in three. Although there is still a substantial degree of visual function deterioration following intracavitary brachytherapy, morbidity is otherwise low, making this treatment modality a reasonable alternative to craniotomy.

Surgical management of giant pediatric craniopharyngiomas

“…Others advocate intracavitary treatments for cystic tumors including irradiation with beta-emitting radioisotopes (phophorus-32 or yttrium-90) 5,33,38,60,61,87,89 or administration of the chemotherapeutic agent bleomycin, an antineoplastic antibiotic that interrupts DNA synthesis. 32,37,54,82 Many reported series utilizing intracavitary therapies are made up of small numbers of patients and usually include small-to moderate-sized, monocystic tumors, not multicystic giant forms.…”

“…Nevertheless, the long-term consequences of using these minimally invasive methods as primary treatment are unclear, and they are not without complications. 37,38,47,54,61,71,87 In terms of radical resection of giant craniopharyngiomas, some authors prefer anterior-to-posterior trajectories, including bilateral subfrontal 2,4 or frontobasal interhemispheric approaches. 76 Others have reported success with lateral trajectories, including pterional 95 and petrosal (presigmoid transtentorial) approaches, the latter specifically for retrochiasmatic tumors.…”

Efficacy of phosphorus-32 brachytherapy without external-beam radiation for long-term tumor control in patients with craniopharyngioma

“…19 A number of studies have assessed this modality since then. 4,5,7,11,17,21,22,27,28 By and large, these studies have shown good cyst control with 1 or more instillations of P32 or yttrium-90. Almost all of these studies (including one from our institution) included patients who underwent multiple modalities of therapy, including varying degrees of resection and EBR.…”

“…Numerous studies have been published on its techniques, indications, and efficacy. 4,5,7,11,12,17,21,[26][27][28] In most studies, brachytherapy is combined with EBR. Previously, we attempted to treat predominantly cystic craniopharyngiomas with brachytherapy alone, withholding external radiation.…”

“…External-beam radiation (EBR), in particular, carries risks of cognitive decline, vision impairment, and endocrine dysfunction. 2,17,27,28 abbreviations EBR = external-beam radiation; MCA = middle cerebral artery; P32 = phosphorus-32. submitted May 21, 2015.…”