title: Tumor volume of growth hormone-secreting pituitary adenomas during treatment with pegvisomant: a prospective multicenter study.
abstract: BACKGROUND
  Clinical and biochemical remission in acromegaly can frequently be achieved with the recombinant GH receptor antagonist pegvisomant, even when other treatments fail. However, increases in tumor volume have been reported.
  
  
  OBJECTIVE
  Because previous studies suffer from inhomogenous magnetic resonance imaging (MRI) protocols, this prospective study examined the long-term course of adenoma volume during pegvisomant therapy by standardized MRI.
  
  
  METHODS
  Five centers in Germany participated. High-resolution MRI was performed at baseline and 6, 12, and 24 months after enrollment.
  
  
  METHODS
  Patients were outpatients, and pegvisomant is third-line therapy in most of the cases.
  
  
  METHODS
  The primary end point was tumor volume at 24 month follow-up, measured by a single, double-blinded rater.
  
  
  RESULTS
  Forty-five of 61 patients completed 24 months' follow-up (73.8%). Tumor volume increase greater than 25% during the study was observed in three of 61 patients (4.9%), all during the first year of enrollment. All three patients had had octreotide treatment before initiation of pegvisomant; none of them had had radiotherapy. All volumetric findings were comparable with clinical radiological interpretations. ANOVA revealed no significant change in tumor volume after 24 months (n = 45).
  
  
  CONCLUSIONS
  This study shows that pegvisomant therapy infrequently coincides with tumor growth during long-term treatment of acromegaly. Because all significant tumor volume increases occurred during the first year, these changes might correlate to the change of medication and thus be the result of a rebound from somatostatin-induced shrinkage.
authors: Department of Neuroradiology, University of Goettingen, Robert Koch Strasse 40, D-37075 Goettingen, Germany. jh.buhk@mac.com
authors: Jan-Hendrik
authors: JH
authors: Buhk
authors: Sabine
authors: S
authors: Jung
authors: Marios Nikos
authors: MN
authors: Psychogios
authors: Sophia
authors: S
authors: Göricke
authors: Sabine
authors: S
authors: Hartz
authors: Susanne
authors: S
authors: Schulz-Heise
authors: Randolf
authors: R
authors: Klingebiel
authors: Michael
authors: M
authors: Forsting
authors: Hartmut
authors: H
authors: Brückmann
authors: Arnd
authors: A
authors: Dörfler
authors: Martina
authors: M
authors: Jordan
authors: Michael
authors: M
authors: Buchfelder
authors: Michael
authors: M
authors: Knauth
mesh_terms: D000236:Adenoma / Q000188:drug therapy* / Q000473:pathology; D000328:Adult; D000368:Aged; D005260:Female; D049912:Growth Hormone-Secreting Pituitary Adenoma / Q000188:drug therapy* / Q000473:pathology; D019382:Human Growth Hormone / Q000031:analogs & derivatives* / Q000627:therapeutic use; D006801:Humans; D007334:Insulin-Like Growth Factor I / Q000032:analysis; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D011986:Receptors, Somatotropin / Q000037:antagonists & inhibitors*
chemical_list: D011986:Receptors, Somatotropin; D019382:Human Growth Hormone; D007334:Insulin-Like Growth Factor I; C406545:pegvisomant