title: Colon cancer in Iceland--a nationwide comparative study on various pathology parameters with respect to right and left tumor location and patients age.
abstract: Increasing evidence suggests genetic, biological and demographical difference between right and left colon cancer. Studies have also indicated age differences in the pathology of colon cancer. There is a scarcity of large-scale studies that closely examine the pathological differences regarding age and tumor location. The aim of our study was to do an extensive comparison of right- and left- sided colon cancers as well as comparing patients <50 years with older patients. A retrospective, population-based study was carried out on all patients with colon cancer in Iceland between 1955 and 2004. A total of 2293 cases were analyzed (1148 men, 1145 women). All histopathology material was re-evaluated. Differences in tumor characteristics between right and left location and younger (<50) and older (≥50) patients was evaluated in particular. Higher TNM-stage, larger tumors, vessel invasion, mucinous type, high grade and expanding tumor border occurred more frequently in right- versus left-sided lesions while annular and polypoid tumors were more common in left-sided tumors (p < 0.05). Young patients had more frequent lymph node metastases, vessel invasion, nonpolypoid lesions and infiltrating tumor border (p < 0.05). Right-sided lesions show more aggressive features, reflected in morphology and stage. Younger patients present more frequently with adverse features than do older patients. Frequency of right- and left-sided colon cancer differs by age with pronounced age-location differences in females. This supports the assumption of differences in etiology and carcinogenesis of right- and left-sided colon cancer, and between young and old patients.
authors.affiliation: Faculty of Medicine, University of Iceland, Reykjavik, Iceland.
authors.forename: Petur
authors.initials: P
authors.lastname: Snaebjornsson
authors.forename: Larus
authors.initials: L
authors.lastname: Jonasson
authors.forename: Thorvaldur
authors.initials: T
authors.lastname: Jonsson
authors.forename: Pall Helgi
authors.initials: PH
authors.lastname: Möller
authors.forename: Asgeir
authors.initials: A
authors.lastname: Theodors
authors.forename: Jon G
authors.initials: JG
authors.lastname: Jonasson
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D003110:Colonic Neoplasms / Q000453:epidemiology* / Q000473:pathology*; D005260:Female; D006801:Humans; D007055:Iceland / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D012189:Retrospective Studies; D055815:Young Adult