title: Prevalence of adenomas and hyperplastic polyps in mismatch repair mutation carriers among CAPP2 participants: report by the colorectal adenoma/carcinoma prevention programme 2.
abstract: OBJECTIVE
  To determine the prevalence of adenomatous and hyperplastic polyps in a large cohort of individuals with a germline mutation in a mismatch repair (MMR) gene, the major genetic determinant of hereditary nonpolyposis colorectal cancer (HNPCC). These prevalences have been estimated previously in smaller studies, and the results have been found to be variable.
  
  
  METHODS
  Colorectal Adenoma/Carcinoma Prevention Programme 2 trial is a chemoprevention trial in people classified as having HNPCC. The 695 patients with a proven germline MMR mutation and documented screening history before the chemoprevention study were the focus of this study. The number, histology, size, and location of polyps found at the participants' first ever colonoscopy were analyzed in a cross-sectional study.
  
  
  RESULTS
  Seventy-four patients (10.6%) were found to have at least one adenoma at first colonoscopy, whereas 37 (5.3%) had at least one hyperplastic polyp. The frequency of an adenoma at first colonoscopy increased from 5.0% (95% CI, 2.8% to 8.3%) in patients younger than 35 years old to 18.9% (95% CI, 9.4% to 32.0%) in patients age at least 55 years (P = .0001 for trend). No such trend was observed for hyperplastic polyps. No sex differences were found for either type of polyp. A marginal association was found between the co-occurrence of adenomas and hyperplastic polyps. Adenomas tended to be more proximally distributed through the colon, whereas hyperplastic polyps tended to be located in the distal colon.
  
  
  CONCLUSIONS
  Adenoma prevalence increases with age among MMR mutation carriers, whereas hyperplastic polyp prevalence is consistent. No sex differences were observed for either type of lesion.
authors.affiliation: The Oncology Unit of Radiumhemmet at Karolinska University Hospital, Stockholm, Sweden. annelieliljegren@yahoo.com
authors.forename: Annelie
authors.initials: A
authors.lastname: Liljegren
authors.forename: Gail
authors.initials: G
authors.lastname: Barker
authors.forename: Faye
authors.initials: F
authors.lastname: Elliott
authors.forename: Lucio
authors.initials: L
authors.lastname: Bertario
authors.forename: Marie Luise
authors.initials: ML
authors.lastname: Bisgaard
authors.forename: Diana
authors.initials: D
authors.lastname: Eccles
authors.forename: Gareth
authors.initials: G
authors.lastname: Evans
authors.forename: Finlay
authors.initials: F
authors.lastname: Macrae
authors.forename: Eamonn
authors.initials: E
authors.lastname: Maher
authors.forename: Annika
authors.initials: A
authors.lastname: Lindblom
authors.forename: Samuel
authors.initials: S
authors.lastname: Rotstein
authors.forename: Bo
authors.initials: B
authors.lastname: Nilsson
authors.forename: Jukka-Pekka
authors.initials: JP
authors.lastname: Mecklin
authors.forename: Gabriela
authors.initials: G
authors.lastname: Möslein
authors.forename: Jeremy
authors.initials: J
authors.lastname: Jass
authors.forename: Riccardo
authors.initials: R
authors.lastname: Fodde
authors.forename: John
authors.initials: J
authors.lastname: Mathers
authors.forename: John
authors.initials: J
authors.lastname: Burn
authors.forename: D Timothy
authors.initials: DT
authors.lastname: Bishop
mesh_terms: D000236:Adenoma / Q000453:epidemiology / Q000235:genetics* / Q000473:pathology / Q000628:therapy; D000328:Adult; D017677:Age Distribution; D000368:Aged; D000704:Analysis of Variance; D003111:Colonic Polyps / Q000453:epidemiology / Q000235:genetics* / Q000473:pathology / Q000628:therapy; D003113:Colonoscopy; D015179:Colorectal Neoplasms / Q000453:epidemiology / Q000235:genetics* / Q000473:pathology / Q000628:therapy; D003123:Colorectal Neoplasms, Hereditary Nonpolyposis / Q000453:epidemiology / Q000235:genetics / Q000473:pathology; D003430:Cross-Sectional Studies; D053843:DNA Mismatch Repair; D005260:Female; D005500:Follow-Up Studies; D020022:Genetic Predisposition to Disease / Q000453:epidemiology*; D018095:Germ-Line Mutation; D006579:Heterozygote; D006801:Humans; D008297:Male; D008875:Middle Aged; D015337:Multicenter Studies as Topic; D015999:Multivariate Analysis; D009367:Neoplasm Staging; D015995:Prevalence; D016016:Proportional Hazards Models; D016032:Randomized Controlled Trials as Topic; D017678:Sex Distribution; D016019:Survival Analysis