Mortality following pituitary radiotherapy

Abstract

External beam radiotherapy has been used in the management of pituitary adenomas for nearly a century, preventing tumor regrowth following surgery for non-functioning pituitary adenomas and suppressing functional hypersecretion in those which are hormonally active. However, it has been linked with a number of potentially significant complications including formation of secondary intracranial tumors, cognitive impairment, hypopituitarism and cerebrovascular disease, as well as increased mortality. Radiation may cause a variety of vascular injuries and hemodynamic changes to the cerebral vasculature, and several authors have reported cerebrovascular complications and an increase in cerebrovascular mortality in patients receiving radiotherapy for pituitary and other central nervous system tumors. Ten years following pituitary radiotherapy, over 50% of patients develop deficiencies in one or more anterior pituitary hormones. A number of studies have demonstrated increased mortality in patients with hypopituitarism, predominantly due to cerebrovascular and cardiovascular disease. However, no clear answer has emerged with regards to causation, and pituitary radiotherapy has only been linked directly to mortality in one of these studies. Questions remain unanswered, and the use of conventional external beam radiotherapy in the management of pituitary disease must involve a critical risk-benefit analysis in each case.