Age-specific prevalence of serrated lesions and their subtypes by screening colonoscopy: a retrospective study

Serrated lesions of the colorectum as categorized by pathology include hyperplastic polyps, sessile serrated adenomas without dysplasia, and traditional serrated adenomas with dysplasia. The aim of this study was to investigate the prevalence of various subtypes of serrated lesions by age.

In this study, 28,544 consecutive asymptomatic patients (aged 22-88 years) were evaluated during health check-ups involving colonoscopies performed by gastroenterologists at a single institution from 2005 to 2012.

The adenoma detection rate during colonoscopies for patients aged ≥50 years was 31.8% (25.0-35.8%). The serrated lesion detection rate for patients aged ≥50 years was 15.3% (10.5-19.6%). Serrated lesions were detected in 15.1% of all patients with subtype prevalences of 14.7% for hyperplastic polyps, 0.5% for sessile serrated adenomas, and 0.1% for traditional serrated adenomas. The prevalence of conventional adenomas increased sharply with age (5.0% in patients aged 20-29 years, 10.9% in those aged 30-39 years, 21.8% in those aged 40-49 years, 29.5% in those aged 50-59 years, 36.9% in those aged 60-69 years, and 40.7% in those aged ≥70 years) (trend P = 0.027). In contrast, the prevalence of serrated lesions increased only slightly with age (10.0% in patients aged 20-29 years, 11.8% in those aged 30-39 years, 14.8% in those aged 40-49 years, 15.3% in those aged 50-59 years, 16.8% in those aged 60-69 years, and 16.4% in those aged ≥70 years) (trend P = 0.036).

The screening colonoscopy detection rate of serrated lesions, including sessile serrated adenomas and traditional serrated adenomas, appears to be relatively high among young patients aged <50 years.