title: Stereotactic Radiosurgery as the Initial Treatment for Patients with Nonfunctioning Pituitary Adenomas.
abstract: OBJECTIVE
  The aim of this study was to confirm the efficacy and safety of stereotactic radiosurgery as the initial treatment for patients with nonfunctioning pituitary adenomas (NFPAs) and to decide the optimum dose to achieve long-term tumor control as well as preservation of pituitary endocrine function.
  
  
  METHODS
  The study was a single-center retrospective analysis of 16 patients with primary NFPAs that were treated with gamma knife surgery (GKS). Fifteen of 16 NFPAs were growing to the suprasellar region and slightly compressing or very close to the optic apparatus. Initial GKS was selected to avoid visual disturbance caused by further tumor growth that would require surgical resection under general anesthesia. The median tumor volume was 2.0 cm(3), and the median tumor margin dose was 15 Gy.
  
  
  RESULTS
  The median clinical follow-up period was 98 months. The last follow-up images demonstrated tumor regression in 15 patients and stable tumor in 1. No patient developed tumor progression. One patient who had pituitary apoplexy before treatment required hormone replacements 2 years after GKS. The other patients did not experience pituitary insufficiency requiring hormone-replacement therapy during the clinical follow-up period. No patient developed cranial nerve injury or radiation-induced neoplasm.
  
  
  CONCLUSIONS
  GKS is a safe and effective treatment option in patients with primary NFPAs, especially for patients with advanced age or comorbidity. Attention should be paid to late adverse radiation effects such as hypopituitarism, optic neuropathy, and radiation-induced neoplasms. However, stereotactic radiosurgery with a conformal treatment plan sparing the normal pituitary gland will contribute to avoidance of such complications as well as achievement of long-term tumor control.
authors.affiliation: Department of Neurosurgery, Gamma Knife Center, Komaki City Hospital, Komaki, Japan. Electronic address: h-toshi@komakihp.gr.jp.
authors.forename: Toshinori
authors.initials: T
authors.lastname: Hasegawa
authors.affiliation: Department of Neurosurgery, Gamma Knife Center, Komaki City Hospital, Komaki, Japan.
authors.forename: Kazunori
authors.initials: K
authors.lastname: Shintai
authors.affiliation: Department of Neurosurgery, Gamma Knife Center, Komaki City Hospital, Komaki, Japan.
authors.forename: Takenori
authors.initials: T
authors.lastname: Kato
authors.affiliation: Department of Neurosurgery, Gamma Knife Center, Komaki City Hospital, Komaki, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Iizuka
mesh_terms: D000236:Adenoma / Q000503:physiopathology / Q000601:surgery*; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D005500:Follow-Up Studies; D020249:Hormone Replacement Therapy; D006801:Humans; D008297:Male; D008875:Middle Aged; D010899:Pituitary Apoplexy / Q000601:surgery; D010911:Pituitary Neoplasms / Q000503:physiopathology / Q000601:surgery*; D016634:Radiosurgery; D020127:Recovery of Function; D012189:Retrospective Studies; D016896:Treatment Outcome; D047368:Tumor Burden
keywords: Gamma knife; Nonfunctioning; Pituitary adenomas; Pituitary hormone; Stereotactic radiosurgery; Tumor control