Adults aged 45 to 49 years at average risk for colorectal cancer (CRC) who had a screening colonoscopy had a 5.0% prevalence of advanced neoplasia, according to a study in Gastroenterology.

Researchers sought to determine the prevalence and predictors of colorectal neoplasia in adults aged younger than 50 years. Using data from the GI Quality Improvement Consortium, a national endoscopy registry, researchers conducted a cross-sectional analysis of all outpatient colonoscopies performed for the indication of screening for colonic neoplasia from January 1, 2010, to December 31, 2020. Procedures from 2010 to 2012 were excluded from the trend analysis due to the small sample size.

The primary outcome was the prevalence of advanced neoplasia in adults aged younger than 50 years.


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Of 3,928,727 total screening colonoscopies included in the study, 211,020 were performed in individuals aged younger than 50 years. Of this group, 129,736 procedures were performed in study participants without a family history of CRC or advanced adenomas. A majority of participants (71.5%) were aged 45 to 49 years, 56.0% were women, 49.2% were White, 16.1% were Black, 5.1% were Hispanic, and 2.8% were Asian.

Among adults aged 45 to 49 years at average risk for CRC, the prevalence of advanced neoplasia and adenoma was 5.0% (prevalence ratio [PR], 0.81; 95% CI, 0.78-0.83) and 28.3% (PR, 0.86; 95% CI, 0.85-0.87), respectively. Compared with the reference group of adults aged 50 to 54 years, the prevalence of advanced neoplasia and adenoma among adults aged 45 to 49 years at average risk for CRC was 19% (PR, 0.81; 95% CI, 0.78-0.83) and 14% (PR, 0.86; 95% CI, 0.85-0.87) lower, respectively.

For all patients aged 45 to 49 years, the prevalence of advanced neoplasia and adenomas was 12% (PR, 0.88; 95% CI, 0.86-0.90) and 13% (PR, 0.87; 95% CI, 0.87-0.88) lower, respectively, compared with the reference group of participants aged 50 to 54 years.

Men had a higher prevalence of advanced neoplasia and adenomas compared with women in all age groups. Women aged 45 to 49 years at average risk for CRC had a comparable prevalence of advanced neoplasia (4.1%) to men aged 30 to 39 years (3.7%). The prevalence of advanced neoplasia among men aged 45 to 49 years at average risk for CRC (6.2%) was most similar to that in women aged 65 to 69 years (6.4%).

Positive predictors for advanced neoplasia in individuals aged younger than 50 years included increasing age (odds ratio [OR], 2.49; 95% CI, 2.05-3.03 for those aged 45 to 49 years compared with those aged 18 to 29 years), male sex (OR, 1.38; 95% CI, 1.32-1.44), family history of advanced adenomas (OR, 1.32; 95% CI, 1.22-1.42) or CRC (OR, 1.17; 95% CI, 1.12-1.23), and obesity (OR, 1.30; 95% CI, 1.20-1.42 vs normal body mass index).

Black (OR, 0.65; 95% CI, 0.61-0.70), Asian (OR, 0.68; 95% CI, 0.59-0.77), and Hispanic (OR, 0.84; 95% CI, 0.77-0.92) individuals were less likely to have advanced neoplasia compared with White individuals.

The proportion of screening colonoscopies in the 45- to 49-year age group increased from 2.9% in 2013 to 5.0% in 2020 (P <.0001). The proportion of procedures by sex was stable over time, with 56.3% of procedures occurring in women in 2020 (P =.40).

Among several study limitations, the data were not population-based, and the researchers were unable to assess the anatomic distribution of colorectal neoplasia by age.

“These findings support initiating screening at age 45 years, demonstrate current adenoma detection benchmarks are applicable in the 45- to 49-year age group, and may inform risk-based screening strategies,” the study authors noted.

Disclosure: One of the study authors declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of authors’ disclosures.

Reference

Liang PS, Williams JL, Dominitz JA, Corley DA, Zauber AG. Age-stratified prevalence and predictors of neoplasia among U.S. adults undergoing screening colonoscopy in a national endoscopy registry. Gastroenterology. Published online May 25, 2022. doi:10.1053/j.gastro.2022.05.036