90Yttrium Colloid for the Treatment of Cystic Sellar/Parasellar Tumors

There is no consensus in the literature on the best way to treat cystic lesions of the pituitary area. Patients who are symptomatic from these tumours are rare. The cystic form of tumours present special challenges since traditional treatment modalities (surgery and/or external radiation) are often not able to completely remove or treat the cyst wall without major morbidity or even mortality. There is no 'best practice' for the treatment of cystic tumours per se. Treatments available to patients with cystic sellar/parasellar tumours include conservative management using a 'wait and scan' approach, cyst drainage, and cyst removal via transsphenoidal and/or craniotomy approach (i.e. open surgery). Over the last 10 years we have treated approximately 8 patients with intracystic radiotherapy. All of these patients continue to be monitored clinically and radiologically and all have done well with stable regression of the cysts and no new neurological deficits. Over the past 2 years, 90yttrium colloid has been provided to CDHA through Health Canada's Special Access Program (SAP). It has only been of recent that Health Canada has requested a clinical trial to assess the benefit of intracystic radiotherapy over other available treatment options. The experimental treatment being proposed is the stereotactic intracavitary instillation of 90yttrium colloid for treatment of cystic lesions of the pituitary (sellar) and surrounding areas (parasellar).