title: Two Phenotypes of Traditional Serrated Adenomas Nationwide Survey in Iceland.
abstract: Iceland has a total population of 300,000 inhabitants. All patients consulting for symptoms of the lower digestive tract during a four-year period (2003-2006) were subjected to a colonoscopic examination; all polyps were endoscopically removed. Out of the total 3,037 colorectal adenomas (CRAs), 308 (10.2%) were traditional serrated adenomas (TSAs). TSAs were divided according the predominant histological phenotype (>50%) into those with ectopic crypt formations (ECF), and those with unlocked serrations (US). ECF-TSA accounted for 5.9% (178/3037) and US-TSA for 4.3% (130/3037). The majority of patients with ECF-TSA and US-TSA were ≥ 60 years of age (74.1% and 76.2%, respectively). Notwithstanding, when patients having advanced adenomas (with high-grade dysplasia, with or without intramucosal carcinoma) were listed by age, those with ECF-TSA were significantly younger than those with US-TSA (p<0.05). ECF-TSA were more frequently left-sided (71.8%), whereas US-TSA were more frequently right-sided (60.0%). Invasive carcinoma evolved more frequently in ECF-TSA (7.8%) and in US-TSA (7.7%) than in tubular adenomas and in villous/tubulovillous adenomas (0.1% and 4.4%, respectively). Comparative studies indicated that the incidence rates/year of ECF-TSA and US-TSA were significantly higher in Iceland than in Sweden or in Italy (p<0.05). Genetic and putative epigenetic (environmental) factor(s) might account for the high incidence rate/year of ECF-TSA and US-TSA in this country.
authors.affiliation: Department of Pathology, Karolinska Institute and University Hospital, Stockholm, Sweden Carlos.Rubio@ki.se.
authors.forename: Carlos A
authors.initials: CA
authors.lastname: Rubio
authors.affiliation: Department of Pathology, University Hospital, Reykjavik, Iceland.
authors.forename: Jón G
authors.initials: JG
authors.lastname: Jónasson
mesh_terms: D000236:Adenoma / Q000453:epidemiology* / Q000473:pathology*; D015179:Colorectal Neoplasms / Q000453:epidemiology* / Q000473:pathology*; D005260:Female; D006306:Health Surveys; D006801:Humans; D007055:Iceland / Q000453:epidemiology; D015994:Incidence; D008297:Male; D008875:Middle Aged; D010641:Phenotype
keywords: Colorectal adenomas; Iceland; incidence rate; invasive carcinoma; nationwide survey; traditional serrated adenomas