Introduction: Colorectal cancer (CRC) is the #2 cancer killer in the US.1 Recently, the USPSTF guidelines reduced the CRC screening age to 45 yo for normal-risk individuals.2 The adenoma detection rate (ADR) of 25% (20% F, 30% M) is an accepted benchmark of a quality colonoscopy in 50-75 yo. Since prevalence of adenomas increases with age, it has been suggested that a 1-3% reduction in ADR can be anticipated in 45-49 yo patients undergoing a screening colonoscopy.3 No studies have evaluated the ADR among 45-49 yo screened in 2021, since the integration of the new guidelines.
Aim: To compare the ADR in screening colonoscopies for patients ages 45-49 yo vs. older cohorts in 2021.
Methods: A retrospective analysis of records was performed on 6386 asymptomatic 45-75 yo patients who underwent a screening colonoscopy. Exclusion criteria included: (1) prior screening test, (2) incomplete colonoscopy, (3) inadequate bowel preparation, or (4) hereditary CRC syndrome/CRC family history. ADR is defined as the percentage of colonoscopies with ≥1 tubular adenoma (TA), tubulovillous adenoma (TVA), or sessile serrated adenoma (SSA).3 An advanced lesion was defined as a TA/SSA >10 mm, villous or high grade dysplasia, traditional serrated adenoma, or >5 adenomas or SSA in any combination, or cancer.3
Results: 5985 colonoscopies (2857 M,3128 F) were performed with an average withdrawal time ~11 minutes. Table 1 shows ADR results.
The 45-49 yo cohort represented 10.9% of the screened population. The ADR in the 45-49 age range was 32.1% vs 38.7% (P< 0.0097) for the 50-75 age cohort.
Discussion: In our study, 10.9% of the screened population was between 45-49 years old. The ADR was significantly lower in the 45-49 yo cohort as compared to the 50-75 yo cohort; however, the 32% ADR remains well above the accepted benchmark of 25%. The APC is lower in 45-49 yo patients, and a larger sample size may show reduction in ADR when compared to 50-54 yo. Gastroenterologists can expect only a slightly lower ADR in the newest screening cohort (age 45-49), but it remains critical that physicians emphasize the importance of average-risk CRC in the younger demographic.
1. Siegel RL, et al. Cancer statistics, 2019. CA Cancer J Clin 2019;69:7-34. 2. US Preventive Services Task Force. Screening for colorectal cancer: US Preventive Services Task Force recommendation statement. JAMA 2021;325:1965-1977. 3. Shaukat A, et al. Adenoma detection for 45- to 49-year-old screening population. Gastroenterology 2022;162:957-959.
