characteristics of colorectal polyps and cancer; a retrospective review of colonoscopy data in iran

background: early diagnosis and endoscopic resection of adenomatous polyps is the main approach for screening and prevention of colorectal cancer (crc). we aimed to assess polyp detection rate (pdr) and to characterize demographic, clinical, and pathological features of colorectal polyps in an iranian population. methods: we retrospectively analyzed the data from 5427 colonoscopies performed during 2007-2012 at masoud clinic, the main endoscopy center associated with sasan alborz biomedical research center, in tehran, iran. results: our sample included 2928 (54%) women and 2499 (46%) men, with the mean age of 48.3 years (sd=16.1). the most common reasons for colonoscopy included screening in 25.0%, and gastrointestinal bleeding in 15.2%. cecal intubation was successful in 86% of patients. the quality of bowel preparation was good to excellent in 78.0% (n=4235) of colonoscopies. overall pdr was 42.0% (95% ci: 40.6-43.3). the pdr in men (51.1%, 95% ci: 49.1-53.1) was significantly higher than women (34.2%, 95% ci: 32.4-35.9, p <0.001). polyps were more frequently observed in patients after the 6 th decade of life (f=3.2; p =0.004). crc was detected in 2.9% (73/2499) of men and 1.9% (57/2928) of women ( p =0.02). the mean age for patients with cancer was significantly higher than that for individuals with polyps, 60.9 (sd=13.4) year vs . 56.9 (sd=13.7) year, respectively ( p =0.001). almost 82.8% of the lesions were precancerous with tubular type predominance (62.3%) followed by tubulo-villous (10.3%), villous (6.6%), and serrated (3.6%). hyperplastic/inflammatory polyps comprised 17.2% of lesions. conclusion: about 50% of polyps more than 10 mm and 65% of colorectal cancers were in the rectum and sigmoid. these findings provide a great infrastructure for next preventive programs and have implications for colorectal cancer screening at population-level.