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Hypopituitarism After Stereotactic Radiosurgery for Pituitary Adenomas

Xu, Zhiyuan MD*; Lee Vance, Mary MD; Schlesinger, David PhD§; Sheehan, Jason P. MD, PhD*

doi: 10.1227/NEU.0b013e3182846e44
Research-Human-Clinical Studies

BACKGROUND: Studies of new-onset Gamma Knife stereotactic radiosurgery (SRS)-induced hypopituitarism in large cohort of pituitary adenoma patients with long-term follow-up are lacking.

OBJECTIVE: We investigated the outcomes of SRS for pituitary adenoma patients with regard to newly developed hypopituitarism.

METHODS: This was a retrospective review of patients treated with SRS at the University of Virginia between 1994 and 2006. A total of 262 patients with a pituitary adenoma treated with SRS were reviewed. Thorough endocrine assessment was performed immediately before SRS and in regular follow-ups. Assessment consisted of 24-hour urine free cortisol (patients with Cushing disease), serum adrenocorticotropic hormone, cortisol, follicle-stimulating hormone, luteinizing hormone, insulin-like growth factor-1, growth hormone, testosterone (men), prolactin, thyroid-stimulating hormone, and free T4.

RESULTS: Endocrine remission occurred in 144 of 199 patients with a functioning adenoma. Tumor control rate was 89%. Eighty patients experienced at least 1 axis of new-onset SRS-induced hypopituitarism. The new hypopituitarism rate was 30% based on endocrine follow-up ranging from 6 to 150 months; the actuarial rate of new pituitary hormone deficiency was 31.5% at 5 years after SRS. On univariate and multivariate analyses, variables regarding the increased risk of hypopituitarism included suprasellar extension and higher radiation dose to the tumor margin; there were no correlations among tumor volume, prior transsphenoidal adenomectomy, prior radiation therapy, and age at SRS.

CONCLUSION: SRS provides an effective and safe treatment option for patients with a pituitary adenoma. Higher margin radiation dose to the adenoma and suprasellar extension were 2 independent predictors of SRS-induced hypopituitarism.

ABBREVIATIONS: CD, Cushing disease

GH, growth hormone

IGF-1, insulin-like growth factor-1

RT, radiation therapy

SRS, stereotactic radiosurgery

TSA, transsphenoidal adenomectomy

Departments of *Neurological Surgery

Medicine, and

§Radiation Oncology, University of Virginia Health Sciences System, Charlottesville, Virginia

Correspondence: Jason Sheehan, MD, PhD, Department of Neurological Surgery, University of Virginia, Charlottesville, VA 22908. E-mail: jsheehan@virginia.edu

Received July 30, 2012

Accepted December 11, 2012

Copyright © by the Congress of Neurological Surgeons