title: Gamma Knife radiosurgery for the management of nonfunctioning pituitary adenomas: a multicenter study.
abstract: OBJECTIVE
  Pituitary adenomas are fairly common intracranial neoplasms, and nonfunctioning ones constitute a large subgroup of these adenomas. Complete resection is often difficult and may pose undue risk to neurological and endocrine function. Stereotactic radiosurgery has come to play an important role in the management of patients with nonfunctioning pituitary adenomas. This study examines the outcomes after radiosurgery in a large, multicenter patient population.
  
  
  METHODS
  Under the auspices of the North American Gamma Knife Consortium, 9 Gamma Knife surgery (GKS) centers retrospectively combined their outcome data obtained in 512 patients with nonfunctional pituitary adenomas. Prior resection was performed in 479 patients (93.6%) and prior fractionated external-beam radiotherapy was performed in 34 patients (6.6%). The median age at the time of radiosurgery was 53 years. Fifty-eight percent of patients had some degree of hypopituitarism prior to radiosurgery. Patients received a median dose of 16 Gy to the tumor margin. The median follow-up was 36 months (range 1-223 months).
  
  
  RESULTS
  Overall tumor control was achieved in 93.4% of patients at last follow-up; actuarial tumor control was 98%, 95%, 91%, and 85% at 3, 5, 8, and 10 years postradiosurgery, respectively. Smaller adenoma volume (OR 1.08 [95% CI 1.02-1.13], p = 0.006) and absence of suprasellar extension (OR 2.10 [95% CI 0.96-4.61], p = 0.064) were associated with progression-free tumor survival. New or worsened hypopituitarism after radiosurgery was noted in 21% of patients, with thyroid and cortisol deficiencies reported as the most common postradiosurgery endocrinopathies. History of prior radiation therapy and greater tumor margin doses were predictive of new or worsening endocrinopathy after GKS. New or progressive cranial nerve deficits were noted in 9% of patients; 6.6% had worsening or new onset optic nerve dysfunction. In multivariate analysis, decreasing age, increasing volume, history of prior radiation therapy, and history of prior pituitary axis deficiency were predictive of new or worsening cranial nerve dysfunction. No patient died as a result of tumor progression. Favorable outcomes of tumor control and neurological preservation were reflected in a 4-point radiosurgical pituitary score.
  
  
  CONCLUSIONS
  Gamma Knife surgery is an effective and well-tolerated management strategy for the vast majority of patients with recurrent or residual nonfunctional pituitary adenomas. Delayed hypopituitarism is the most common complication after radiosurgery. Neurological and cranial nerve function were preserved in more than 90% of patients after radiosurgery. The radiosurgical pituitary score may predict outcomes for future patients who undergo GKS for a nonfunctioning adenoma.
authors.affiliation: Department of Neurological Surgery, University of Virginia Health System, Charlottesville, VA, USA.
authors.forename: Jason P
authors.initials: JP
authors.lastname: Sheehan
authors.forename: Robert M
authors.initials: RM
authors.lastname: Starke
authors.forename: David
authors.initials: D
authors.lastname: Mathieu
authors.forename: Byron
authors.initials: B
authors.lastname: Young
authors.forename: Penny K
authors.initials: PK
authors.lastname: Sneed
authors.forename: Veronica L
authors.initials: VL
authors.lastname: Chiang
authors.forename: John Y K
authors.initials: JY
authors.lastname: Lee
authors.forename: Hideyuki
authors.initials: H
authors.lastname: Kano
authors.forename: Kyung-Jae
authors.initials: KJ
authors.lastname: Park
authors.forename: Ajay
authors.initials: A
authors.lastname: Niranjan
authors.forename: Douglas
authors.initials: D
authors.lastname: Kondziolka
authors.forename: Gene H
authors.initials: GH
authors.lastname: Barnett
authors.forename: Stephen
authors.initials: S
authors.lastname: Rush
authors.forename: John G
authors.initials: JG
authors.lastname: Golfinos
authors.forename: L Dade
authors.initials: LD
authors.lastname: Lunsford
mesh_terms: D000236:Adenoma / Q000150:complications / Q000473:pathology / Q000601:surgery*; D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D018572:Disease-Free Survival; D005260:Female; D006801:Humans; D007018:Hypopituitarism / Q000209:etiology / Q000473:pathology / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D010911:Pituitary Neoplasms / Q000150:complications / Q000473:pathology / Q000601:surgery*; D016634:Radiosurgery / Q000295:instrumentation*; D012189:Retrospective Studies; D016896:Treatment Outcome