Treatment of cystic craniopharyngioma with phosphorus-32 intracavitary irradiation

Abstract

Purpose The aim of the study was to evaluate the effect of phosphorus-32 colloid ([32P]) intracavitary irradiation on the treatment of patients with cystic craniopharyngiomas. Methods Twenty patients with predominantly cystic craniopharyngiomas were admitted from 1981 to 2006. Eleven patients had [32P] intracavitary irradiation by stereotactic injection or Ommaya cyst instillation as the primary treatment, and the remaining nine had the same internal irradiation as an adjuvant treatment after tumor resection. A calculated irradiation dose of 400~500 Gy per once was delivered to the cyst wall. Conclusion The patients were followed up ranging from 36 to 336 months; no operative morbidity or mortality was found from [32P] intracavitary irradiation. Fourteen patients (70%) had tumor progression and required further two to four times intracavitary irradiation. All 20 cases achieved tumor shrinkage or stabilization with effective outcome 3–6 months after the last [32P] therapy. For patients with cystic craniopharyngioma, [32P] administration by stereo-tactic injection or Ommaya cyst instillation is a safe and helpful option, which could improve the life quality, prolong the life span, and enhance the survival rate of cystic craniopharyngioma patients.

Intracavitary Irradiation as a Safe Alternative for Cystic Craniopharyngiomas: Case Report and Review of the Literature

“…The intracavitary irradiation approach is achieved using beta radiation emitting radioisotopes such as 90 Y, 186 Re, and 32 P applied into the cyst using stereotactic or neuroendoscopic approaches [ 4 , 10 , 11 ]. The therapeutic range is only a few millimeters, allowing the destruction of the cyst lining secretory epithelium and stopping fluid production, thus subsequently reducing the cyst size and promoting the adhesion of the cyst wall [ 4 , 12 ]. This can be achieved because radioisotopes allow delivery of higher doses of radiation directly into the inner surface of the cyst without affecting the surrounding brain structures; this is in contrast to the results obtained using conventional external beam radiotherapy techniques [ 6 , 12 ].…”

“…The therapeutic range is only a few millimeters, allowing the destruction of the cyst lining secretory epithelium and stopping fluid production, thus subsequently reducing the cyst size and promoting the adhesion of the cyst wall [ 4 , 12 ]. This can be achieved because radioisotopes allow delivery of higher doses of radiation directly into the inner surface of the cyst without affecting the surrounding brain structures; this is in contrast to the results obtained using conventional external beam radiotherapy techniques [ 6 , 12 ]. The radiation dose that can be administered by beta radiation emitting radioisotopes to the cyst is between 90 and 300 Gy [ 13 – 16 ].…”

“…Despite these negative aspects of the treatment, favorable results are far more frequent than unfavorable results. The radioactivity dose does, however, need to be carefully selected, in order to achieve a safe yet effective treatment, reducing the risk of radiation accidents [ 4 , 12 ].…”

Pediatric Radiation

“…A pediatric neurosurgeon and radiation oncologist administer this treatment jointly. Beta-emitting particles (P32 or Y90) are administered by stereotactic cannulation of the cyst, or via an Ommaya reservoir if placement allows (Zhao et al, 2010). Cysts are often drained at the time of intracavitary treatment and a colloid suspension containing the radioactive particles is administered.…”

Stereotactic intracavitary brachytherapy with P-32 for cystic craniopharyngiomas in children

“…Zhao et al [42] used P-32 for intracavitary brachytherapy in 20 pediatric patients between 1981 and 2006. The reported local tumor control rate was 100 % 3-6 months after treatment.…”