An Adjusted Level of Adenoma Detection Rate is Necessary for Adults Below 50 Years Old

Although adenoma prevalence is lower in younger people compared with screening-aged adults 50 years old and above, there is no adjustment recommendation for the target adenoma detection rate (ADR) in young people. Herein, we estimated a different target ADR for adults below 50 years old based on screening colonoscopy findings.

Asymptomatic, average-risk adults below 50 years old who underwent screening colonoscopy were enrolled at 12 endoscopy centers in Korea between February 2006 and March 2012. Screening colonoscopies were stratified into low or high ADR groups with ADR levels of 20% and 25%, respectively.

The ADRs from 12 endoscopy centers ranged from 12.1% to 43.8% (median ADR, 24.1%) based on 5272 young adults receiving screening colonoscopies. Using 20% as an ADR level, the risks for metachronous adenoma and advanced adenoma were significantly higher in the low ADR group than the high ADR group (35.4% vs. 25.7%, P<0.001; 8.3% vs. 3.7%, P=0.001, respectively). However, using ADR level of 25%, the risk for metachronous neoplasia was similar in the high and low ADR groups in young adults according to screening colonoscopy. In subgroup analysis, similar findings were found in males, but not in females.

Optimal target ADR may be different between younger and older populations, and the adoption of a 20% target ADR could be used as a performance indicator for young populations.