title: Exogenous insulin treatment after hypofractionated radiotherapy in cats with diabetes mellitus and acromegaly.
abstract: BACKGROUND
  The optimal treatment for feline acromegaly has yet to be established. Surgical and medical therapies are minimally effective although radiotherapy might have greater efficacy. The purpose of this study was to review the response and outcome of cats with acromegaly and insulin-resistant diabetes mellitus (DM) to radiotherapy.
  
  
  OBJECTIVE
  That radiotherapy improves glycemic control in cats with acromegaly and that improved glycemic control is due to remission of clinical acromegaly; demonstrated by a fall in serum insulin-like growth factor-1 (IGF-1) concentrations.
  
  
  METHODS
  Fourteen cats with naturally occurring acromegaly.
  
  
  METHODS
  Retrospective case review; records of all cats treated for acromegaly with radiotherapy were reviewed from 1997 to 2008. Cats were selected on the basis of compatible clinical signs, laboratory features, and diagnostic imaging findings. Fourteen cats received radiotherapy, delivered in 10 fractions, 3 times a week to a total dose of 3,700 cGy.
  
  
  RESULTS
  Thirteen of 14 cats had improved diabetic control after radiotherapy. These improvements were sustained for up to 60 months. DM progressed in 2 cats and 1 did not respond. Seven cats responded before the final treatment. Ten cats were euthanized, 1 as a consequence of radiotherapy. In 8 cats in which IGF-1 was measured after treatment, changes in its concentration did not reflect the clinical improvement in glycemic control.
  
  
  CONCLUSIONS
  Radiotherapy represents an effective treatment for cats with insulin-resistant DM resulting from acromegaly. IGF-1 concentration after treatment does not provide a suitable method by which remission from either acromegaly or insulin-resistant DM may be assessed.
authors.affiliation: Department of Veterinary Medicine, University of Cambridge, Cambridge, UK. mark@andersonsturgess.com
authors.forename: M D
authors.initials: MD
authors.lastname: Dunning
authors.forename: C S
authors.initials: CS
authors.lastname: Lowrie
authors.forename: N H
authors.initials: NH
authors.lastname: Bexfield
authors.forename: J M
authors.initials: JM
authors.lastname: Dobson
authors.forename: M E
authors.initials: ME
authors.lastname: Herrtage
mesh_terms: D000172:Acromegaly / Q000150:complications / Q000378:metabolism / Q000532:radiotherapy* / Q000662:veterinary*; D000818:Animals; D001786:Blood Glucose / Q000378:metabolism; D002371:Cat Diseases / Q000188:drug therapy / Q000378:metabolism / Q000532:radiotherapy*; D002415:Cats; D003922:Diabetes Mellitus, Type 1 / Q000150:complications / Q000378:metabolism / Q000532:radiotherapy* / Q000662:veterinary*; D005260:Female; D019270:Fructosamine / Q000097:blood; D007328:Insulin / Q000008:administration & dosage*; D007334:Insulin-Like Growth Factor I / Q000378:metabolism; D008297:Male; D012189:Retrospective Studies
chemical_list: D001786:Blood Glucose; D007328:Insulin; D019270:Fructosamine; D007334:Insulin-Like Growth Factor I