title: The Influence of Pituitary Size on Outcome After Transsphenoidal Hypophysectomy in a Large Cohort of Dogs with Pituitary-Dependent Hypercortisolism.
abstract: BACKGROUND
  Transsphenoidal hypophysectomy is one of the treatment strategies in the comprehensive management of dogs with pituitary-dependent hypercortisolism (PDH).
  
  
  OBJECTIVE
  To describe the influence of pituitary size at time of pituitary gland surgery on long-term outcome.
  
  
  METHODS
  Three-hundred-and-six dogs with PDH.
  
  
  METHODS
  Survival and disease-free fractions were analyzed and related to pituitary size; dogs with and without recurrence were compared.
  
  
  RESULTS
  Four weeks after surgery, 91% of dogs were alive and remission was confirmed in 92% of these dogs. The median survival time was 781 days, median disease-free interval was 951 days. Over time, 27% of dogs developed recurrence of hypercortisolism after a median period of 555 days. Dogs with recurrence had significantly higher pituitary height/brain area (P/B) ratio and pre-operative basal urinary corticoid-to-creatinine ratio (UCCR) than dogs without recurrence. Survival time and disease-free interval of dogs with enlarged pituitary glands was significantly shorter than that of dogs with a non-enlarged pituitary gland. Pituitary size at the time of surgery significantly increased over the 20-year period. Although larger tumors have a less favorable prognosis, outcome in larger tumors improved over time.
  
  
  CONCLUSIONS
  Transsphenoidal hypophysectomy is an effective treatment for PDH in dogs, with an acceptable long-term outcome. Survival time and disease-free fractions are correlated negatively with pituitary gland size, making the P/B ratio an important pre-operative prognosticator. However, with increasing experience, and for large tumors, pituitary gland surgery remains an option to control the pituitary mass and hypercortisolism.
authors.affiliation: Department of Clinical Sciences of Companion Animals, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands.
authors.forename: S J
authors.initials: SJ
authors.lastname: van Rijn
authors.affiliation: Department of Clinical Sciences of Companion Animals, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands.
authors.forename: S
authors.initials: S
authors.lastname: Galac
authors.affiliation: Department of Clinical Sciences of Companion Animals, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands.
authors.forename: M A
authors.initials: MA
authors.lastname: Tryfonidou
authors.affiliation: Department of Clinical Sciences of Companion Animals, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands.
authors.forename: J W
authors.initials: JW
authors.lastname: Hesselink
authors.affiliation: Department of Clinical Sciences of Companion Animals, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands.
authors.forename: L C
authors.initials: LC
authors.lastname: Penning
authors.affiliation: Department of Clinical Sciences of Companion Animals, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands.
authors.forename: H S
authors.initials: HS
authors.lastname: Kooistra
authors.affiliation: Department of Clinical Sciences of Companion Animals, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands.
authors.forename: B P
authors.initials: BP
authors.lastname: Meij
mesh_terms: D000818:Animals; D004283:Dog Diseases / Q000601:surgery*; D004285:Dogs; D007016:Hypophysectomy / Q000379:methods / Q000662:veterinary*; D047748:Pituitary ACTH Hypersecretion / Q000601:surgery / Q000662:veterinary*; D010902:Pituitary Gland / Q000473:pathology* / Q000601:surgery; D012008:Recurrence; D016019:Survival Analysis
keywords: Canine; Cushing's disease; Kaplan-Meier; Pituitary surgery