title: Hypopituitarism after stereotactic radiosurgery for pituitary adenomas.
abstract: 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 T(4).
  
  
  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.
  
  
  CONCLUSIONS
  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.
authors.affiliation: Department of Neurological Surgery, University of Virginia Health Sciences System, Charlottesville, VA, USA.
authors.forename: Zhiyuan
authors.initials: Z
authors.lastname: Xu
authors.forename: Mary
authors.initials: M
authors.lastname: Lee Vance
authors.forename: David
authors.initials: D
authors.lastname: Schlesinger
authors.forename: Jason P
authors.initials: JP
authors.lastname: Sheehan
mesh_terms: D000236:Adenoma / Q000175:diagnosis / Q000453:epidemiology / Q000601:surgery*; D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007018:Hypopituitarism / Q000175:diagnosis* / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D010911:Pituitary Neoplasms / Q000175:diagnosis / Q000453:epidemiology / Q000601:surgery*; D011183:Postoperative Complications / Q000175:diagnosis* / Q000453:epidemiology; D016634:Radiosurgery / Q000009:adverse effects / Q000639:trends*; D012189:Retrospective Studies; D055815:Young Adult