title: Meta-analysis on the effects of octreotide on tumor mass in acromegaly.
abstract: BACKGROUND
  The long-acting somatostatin analogue octreotide is used either as an adjuvant or primary therapy to lower growth hormone (GH) levels in patients with acromegaly and may also induce pituitary tumor shrinkage.
  
  
  OBJECTIVE
  We performed a meta-analysis to accurately assess the effect of octreotide on pituitary tumor shrinkage.
  
  
  METHODS
  A computerized Medline and Embase search was undertaken to identify potentially eligible studies.
  
  
  METHODS
  Eligibility criteria included treatment with octreotide, availability of numerical metrics on tumor shrinkage and clear definition of a clinically relevant reduction in tumor size. Primary endpoints included the proportion of patients with tumor shrinkage and mean percentage reduction in tumor volume.
  
  
  METHODS
  The electronic search identified 2202 articles. Of these, 41 studies fulfilling the eligibility criteria were selected for data extraction and analysis. In total, 1685 patients were included, ranging from 6 to 189 patients per trial. For the analysis of the effect of octreotide on pituitary tumor shrinkage a random effect model was used to account for differences in both effect size and sampling error.
  
  
  RESULTS
  Octreotide was shown to induce tumor shrinkage in 53.0% [95% CI: 45.0%-61.0%] of treated patients. In patients treated with the LAR formulation of octreotide, this increased to 66.0%, [95% CI: 57.0%-74.0%). In the nine studies in which tumor shrinkage was quantified, the overall weighted mean percentage reduction in tumor size was 37.4% [95% CI: 22.4%-52.4%], rising to 50.6% [95% CI: 42.7%-58.4%] with octreotide LAR.
  
  
  CONCLUSIONS
  Most trials examined were open-label and had no control group.
  
  
  CONCLUSIONS
  Octreotide LAR induces clinically relevant tumor shrinkage in more than half of patients with acromegaly.
authors.affiliation: Department of Medical and Surgical Sciences, University of Brescia, Montichiari Hospital, Brescia, Italy. a.giustina@libero.it
authors.forename: Andrea
authors.initials: A
authors.lastname: Giustina
authors.forename: Gherardo
authors.initials: G
authors.lastname: Mazziotti
authors.forename: Valter
authors.initials: V
authors.lastname: Torri
authors.forename: Maurizio
authors.initials: M
authors.lastname: Spinello
authors.forename: Irene
authors.initials: I
authors.lastname: Floriani
authors.forename: Shlomo
authors.initials: S
authors.lastname: Melmed
mesh_terms: D000172:Acromegaly / Q000150:complications* / Q000188:drug therapy*; D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000970:Antineoplastic Agents / Q000494:pharmacology* / Q000627:therapeutic use*; D002986:Clinical Trials as Topic; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015282:Octreotide / Q000494:pharmacology* / Q000627:therapeutic use*; D010911:Pituitary Neoplasms / Q000150:complications / Q000188:drug therapy / Q000473:pathology; D047368:Tumor Burden / Q000187:drug effects*; D055815:Young Adult
chemical_list: D000970:Antineoplastic Agents; D015282:Octreotide