Objectives: To investigate the prevalence of colorectal adenomas and other advanced lesions in first degreerelatives of Iranian patients diagnosed with colorectal cancer by colonoscopy and pathologic evaluation. Methods:Iranian colorectal cancer patients (probands) were identified through pathologic reports of the regional cancerregistry. First degree relatives (siblings, parents and offspring) of probands were evaluated for the existence ofpolyps and precancerous lesions via colonoscopy screening. Control patients were chosen among average riskpopulation with no family history of colorectal cancer who agreed to colonoscopy screening. Results: A total of184 subjects underwent colonoscopy screening from April 2007 to March 2009. From 90 cases among familiesof probands, 70 (77.8%) had a normal colonoscopy result, 18 (20%) demonstrated polyps and 2 (2.2%) werediagnosed with colorectal cancer. Colonoscopy screening in 94 average risk control patients discovered polypsin 4 (4.3%) cases and the other 90 (95.7%) patients had normal total colonoscopy results. Mean age of caseswith advanced lesions was 48.4±10.2 and 41.5±18.4 in control patients with polyps. The incidence of polyps wassignificantly higher in males, and in family case patients compared to controls. Conclusions: Based on colonoscopyscreening, the prevalence of colorectal adenoma and precancerous lesions in first degree relatives of patientsdiagnosed with colorectal cancer is significantly higher than in the average risk population.
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