Radiosurgery for pituitary adenomas.

Stereotactic radiosurgery has been used to manage patients with pituitary adenomas for over 30 years. Numerous studies have documented that more than 95% of pituitary adenoma patients have either tumor shrinkage or stabilization after radiosurgery. Biochemical remission is possible in approximately 80% of properly selected patients with hormone-producing pituitary adenomas. The time to endocrine normalization typically ranges from 1 to 5 years. Factors associated with endocrine cure include the absence of pituitary suppressive medications at the time of radiosurgery and higher radiation doses. Delayed anterior pituitary deficits occur in 20-50% of patients depending on the length and quality of the endocrine follow-up. Visual loss after radiosurgery is rare if the maximum radiation dose to the optic apparatus is kept below 12 Gy. Since the effects of radiosurgery are gradual compared to surgical removal of pituitary adenomas, surgical resection remains the primary therapy for the majority of patients with large tumors causing visual loss or for patients with symptomatic acromegaly or Cushing's disease. However, radiosurgery is effective for pituitary adenoma patients with persistent or recurrent tumors after prior surgery, or for patients considered high risk for open surgical procedures due to coexisting medical conditions.