title: Six-month preoperative octreotide treatment in unselected, de novo patients with acromegaly: effect on biochemistry, tumour volume, and postoperative cure.
abstract: OBJECTIVE
  Treatment with somatostatin analogues is the primary medical treatment of acromegaly. Controversies still exist whether acute octreotide effect predicts long-term biochemical effects, tumour regression or surgical cure. This prospective study investigates effect of 6-month treatment with octreotide long-acting repeatable (LAR) on insulin-like growth factor-1 (IGF-1) and growth hormone (GH) levels, pituitary function, tumour regression and postoperative cure in de novo acromegalic patients.
  
  
  METHODS
  After a baseline evaluation including fasting hormone levels, MRI scan and an acute 50 μg octreotide test, 32 patients were treated with octreotide LAR 20 mg every 28th day for 6 months before surgery. Treatment effects on IGF-1 and GH levels, serum hormone levels and tumour volume were monitored. Surgical cure was evaluated 3 months postoperatively.
  
  
  RESULTS
  Mean tumour volume reduction was 35%, in one-third of the patients more than 50%, while approximately one-third achieved biochemical remission evaluated by normalized IGF-1 levels. The GH reduction following an acute octreotide test was 81 ± 19% and associated with long-term GH reduction (r = 0·78, P < 0·0005). However, neither acute (r = 0·29, P = 0·12) nor the long-term octreotide effect (r = 0·11, P = 0·58) on GH levels was associated with tumour volume reduction and did not predict subsequent surgical cure.
  
  
  CONCLUSIONS
  Six months of long-acting octreotide using a fixed dose, 1/3 of the patients came in biochemical remission, while 2/3 had significant tumour reduction. Moreover, an acute effect of octreotide seemed to be a prerequisite for long-term effect.
authors.affiliation: Unit of Applied Clinical Research, Department of Cancer Research and Molecular Medicine, Norwegian University for Science and Technology, Trondheim, Norway. sven.carlsen@ntnu.no
authors.forename: Sven M
authors.initials: SM
authors.lastname: Carlsen
authors.forename: Johan
authors.initials: J
authors.lastname: Svartberg
authors.forename: Thomas
authors.initials: T
authors.lastname: Schreiner
authors.forename: Sylvi
authors.initials: S
authors.lastname: Aanderud
authors.forename: Oivind
authors.initials: O
authors.lastname: Johannesen
authors.forename: Svein
authors.initials: S
authors.lastname: Skeie
authors.forename: Morten
authors.initials: M
authors.lastname: Lund-Johansen
authors.forename: Stine L
authors.initials: SL
authors.lastname: Fougner
authors.forename: Jens
authors.initials: J
authors.lastname: Bollerslev
mesh_terms: D000172:Acromegaly / Q000097:blood / Q000188:drug therapy* / Q000473:pathology; D000328:Adult; D018931:Antineoplastic Agents, Hormonal / Q000627:therapeutic use; D005260:Female; D005951:Glucose Tolerance Test; D019382:Human Growth Hormone / Q000097:blood; D006801:Humans; D007334:Insulin-Like Growth Factor I / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D015282:Octreotide / Q000627:therapeutic use*; D010901:Pituitary Function Tests; D010911:Pituitary Neoplasms / Q000188:drug therapy* / Q000473:pathology / Q000601:surgery; D011182:Postoperative Care; D011300:Preoperative Care; D011446:Prospective Studies; D012074:Remission Induction; D013997:Time Factors; D016896:Treatment Outcome; D047368:Tumor Burden / Q000187:drug effects*
chemical_list: D018931:Antineoplastic Agents, Hormonal; D019382:Human Growth Hormone; D007334:Insulin-Like Growth Factor I; D015282:Octreotide