Prevalence of adenomas and hyperplastic polyps in mismatch repair mutation carriers among CAPP2 participants: report by the colorectal adenoma/carcinoma prevention programme 2.
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.
Liljegren
Annelie
A
The Oncology Unit of Radiumhemmet at Karolinska University Hospital, Stockholm, Sweden. annelieliljegren@yahoo.com
Barker
Gail
G
Elliott
Faye
F
Bertario
Lucio
L
Bisgaard
Marie Luise
ML
Eccles
Diana
D
Evans
Gareth
G
Macrae
Finlay
F
Maher
Eamonn
E
Lindblom
Annika
A
Rotstein
Samuel
S
Nilsson
Bo
B
Mecklin
Jukka-Pekka
JP
Möslein
Gabriela
G
Jass
Jeremy
J
Fodde
Riccardo
R
Mathers
John
J
Burn
John
J
Bishop
D Timothy
DT
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