Increased in prevalence of advanced colonic polyps in young patients over the past eight years in Hong Kong

Abstract

Background: In Hong Kong, CRC is ranked as the second most common cancer regarding to incidence. Previous studies have shown a change in the distribution of CRC as well as the age of onset. Aim: This study investigated the distribution of advanced polyps, in increasing time, with regard to the prevalence, the histopathological features, such as histology. Methods: During the study period 1998 to 2005, 6424 colonoscopies have been reviewed. Advanced polyp was defined as a polyp ≥ 10 mm in diameter, an adenoma with villous component, or an adenoma with moderate to severe dysplasia. Polyps are considered right sided if they occurred proximal to the splenic flexure and left sided if they occurred distal to the splenic flexure. All the polyps were divided into two groups based upon the year of the examination: period I is from 1998 to 2001 and period II from 2002-2005. Results: 1856 polyps were detected from 6424 colonoscopies. Among them, 613 (33.0%) were advanced polyps. The male to female ratio of advanced polyps was 1.74. The ages of the 359 patients with advanced polyps during the 8 years ranged from 22 to 91 year, with a mean of 69.21 year. Advanced polyps were mainly left sided (59.5%) in the whole study period. The proportion of advanced polyps of age ≤ 60 years increased from 17.7% in period I to 26.3% in period II (P=0.014). The proportion of advanced tubulovillous polyps rose from 21.5% in period I to 29.5% in period II (P= 0.031). Conclusions: These data confirm an increase of advanced polyps in the younger age group in time, which suggest that the importance of screening by colonoscopy for advanced polyps increases in younger people.