Colonic polyp histopathology and location in a community-based sample of older adults.

BACKGROUND: Colorectal cancer and its precursors are highly prevalent in developed countries. Estimates in the available literature for prevalence of right-sided-only lesions vary between 20.5 and 48.1 %, with association with female gender and advancing age. Since the original polyp studies, premalignant potential of sessile serrated adenomas has been described and screening utilization of colonoscopy in men, women, and older adults has increased. This study describes the histopathology and distribution of colorectal polyps by age and gender in the post-screening era.

METHODS: A registry of biopsies performed during colonoscopy for adults aged 50+ years in 2002-2012 was created using pathology reports from an independent, regional laboratory. Age, histopathology, and polyp location(s) were included. A subgroup analysis was performed for sessile serrated adenomas for 2007-2012. Distributions of histopathology and polyp location were described by age and gender. Statistical comparisons are made using chi-square tests.

RESULTS: 13,881 patients (55.5 % male, 44.5 % female), aged 50-95 years (median = 62) were identified. Most patients (59.9 %) had adenomas. Single and multiple adenomas were more common in men than women (57.7 % vs 42.3 %, p < .0001 and 62.2 % vs 37.8 %, p < .001), and with advancing age (60.4 % for ages 50- < 60, 63.4 % for ages 60- < 70, 65 % for ages 70- < 80, and 68.9 % for ages >80). Villous adenomas (n = 545; 3.6 %), dysplasia (n = 49; 0.4 %), and invasive carcinoma (n = 22; 0.2 %) were rare. Sessile serrated adenomas were uncommon (n = 417, 4.5 %), with greater prevalence in women than men (5.1 % vs 4 %, p = 0.02). Patients aged 70- < 80 were more likely to have multiple polyps than those aged 50- < 60 (OR 1.17, 95 % CI 1.03-1.32, p = 0.018 and OR 1.27, 95 % CI 1.10-1.46, p = .001). Most polyps were from ascending and/or transverse colon (n = 8095; 58.3 %). When location was stratified by sex only, men had more polyps than women at each location except the sigmoid and rectum. Further stratification by age of location and sex revealed statistically significant differences (age 50- < 60, p < .0001, age 60- < 70, p = .0227, age 70- < 80, p = .0298, age 80+, p = .0018).

CONCLUSIONS: This large community-based sample contributes to understanding of colonic neoplasia. The high prevalence of right and transverse lesions supports ongoing use of colonoscopy over sigmoidoscopy for screening examinations.