title: Initial Gamma Knife radiosurgery for nonfunctioning pituitary adenomas.
abstract: OBJECTIVE
  Nonfunctioning pituitary adenomas (NFAs) are the most common type of pituitary adenoma and, when symptomatic, typically require surgical removal as an initial means of management. Gamma Knife radiosurgery (GKRS) is an alternative therapeutic strategy for patients whose comorbidities substantially increase the risks of resection. In this report, the authors evaluated the efficacy and safety of initial GKRS for NFAs.
  
  
  METHODS
  An international group of three academic Gamma Knife centers retrospectively reviewed outcome data in 569 patients with NFAs.
  
  
  RESULTS
  Forty-one patients (7.2%) underwent GKRS as primary management for their NFAs because of an advanced age, multiple comorbidities, or patient preference. The median age at the time of radiosurgery was 69 years. Thirty-seven percent of the patients had hypopituitarism before GKRS. Patients received a median tumor margin dose of 12 Gy (range 6.2-25.0 Gy) at a median isodose of 50%. The overall tumor control rate was 92.7%, and the actuarial tumor control rate was 94% and 85% at 5 and 10 years postradiosurgery, respectively. Three patients with tumor growth or symptom progression underwent resection at 3, 3, and 96 months after GKRS, respectively. New or worsened hypopituitarism developed in 10 patients (24%) at a median interval of 37 months after GKRS. One patient suffered new-onset cranial nerve palsy. No other radiosurgical complications were noted. Delayed hypopituitarism was observed more often in patients who had received a tumor margin dose > 18 Gy (p = 0.038) and a maximum dose > 36 Gy (p = 0.025).
  
  
  CONCLUSIONS
  In this study, GKRS resulted in long-term control of NFAs in 85% of patients at 10 years. This experience suggests that GKRS provides long-term tumor control with an acceptable risk profile. This approach may be especially valuable in older patients, those with multiple comorbidities, and those who have endocrine-inactive tumors without visual compromise due to mass effect of the adenoma.
authors.affiliation: Department of Neurological Surgery, University of Virginia Health System, Charlottesville, Virginia;
authors.forename: Cheng-Chia
authors.initials: CC
authors.lastname: Lee
authors.forename: Hideyuki
authors.initials: H
authors.lastname: Kano
authors.forename: Huai-Che
authors.initials: HC
authors.lastname: Yang
authors.forename: Zhiyuan
authors.initials: Z
authors.lastname: Xu
authors.forename: Chun-Po
authors.initials: CP
authors.lastname: Yen
authors.forename: Wen-Yuh
authors.initials: WY
authors.lastname: Chung
authors.forename: David Hung-Chi
authors.initials: DH
authors.lastname: Pan
authors.forename: L Dade
authors.initials: LD
authors.lastname: Lunsford
authors.forename: Jason P
authors.initials: JP
authors.lastname: Sheehan
mesh_terms: D000236:Adenoma / Q000453:epidemiology / Q000601:surgery*; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015897:Comorbidity; D003389:Cranial Nerve Diseases / Q000209:etiology; D018572:Disease-Free Survival; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007018:Hypopituitarism / Q000453:epidemiology / Q000209:etiology / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D010911:Pituitary Neoplasms / Q000453:epidemiology / Q000601:surgery*; D016634:Radiosurgery / Q000009:adverse effects / Q000379:methods*; D012189:Retrospective Studies; D012307:Risk Factors