Results of the largest study of screening colonoscopies in average-risk adults younger than age 50 provide strong support for lowering the screening age to 45 years, by showing a “substantial” prevalence of advanced neoplasia in this age group.
“We found that 5% of average-risk persons aged 45-49 years had advanced neoplasia and 28% had adenoma, which supports lowering the screening age to 45 years and maintaining the current adenoma detection benchmarks,” lead investigator Peter S. Liang, assistant professor of medicine and population health, NYU Grossman School of Medicine in New York City, told Medscape Medical News.
The adenoma prevalence, or adenoma detection rate (ADR), in average-risk adults younger than age 50 was 23.5% in women, 34.4% in men, and 28.3% overall, which implies that the current ADR benchmarks of 20% for women, 30% for men, and 25% overall could be maintained for younger screening participants, Liang and colleagues say.
The study was published May 25 in the journal Gastroenterology.
Benefit Before Age 50 Confirmed
The prevalence of advanced neoplasia and adenomas among average-risk adults younger than age 50 has not been well characterized.
This study provides “the most accurate estimate of neoplasia prevalence in individuals aged 45-49 years — who are newly joining the screening pool — as well as other individuals across the age spectrum,” Liang told Medscape Medical News.
Using a large US endoscopy registry, the researchers calculated age-stratified prevalence and predictors of colonic neoplasia based on more than 3.9 million screening colonoscopies, of which 3.3% were performed in average-risk adults younger than age 50.
The prevalence of advanced neoplasia and adenomas in 45-49 year-olds was 5% and 28.3%, respectively. In 50-54 year-olds, the prevalence was 6.2% and 33%, respectively.
Among 45-49 year-olds, the rates of advanced neoplasia and adenomas were higher in men (6.2% and 34.4%, respectively) than women (4.1% and 23.5%, respectively).
Men had a higher prevalence of neoplasia than women for every age group studied, and the prevalence of advanced neoplasia in average-risk men aged 45-49 years was comparable to that of women aged 65-69 years (6.2% and 6.4%, respectively).
In adults younger than age 50, predictors of advanced neoplasia on multivariable logistic regression included older age, male sex, family history of colorectal cancer (CRC) or advanced adenomas, and obesity.
By race, White adults had a higher prevalence of advanced neoplasia than Black, Hispanic, and Asian individuals across the age spectrum, which was partially driven by serrated lesions.
Overall, the findings support starting CRC screening at age 45 years, “which will likely result in a level of protection against CRC in this younger age group that is clinically comparable to the 50-54 year age group,” Liang and colleagues write.
Weighing in on the findings, Andrew T. Chan, MD, MPH, a gastroenterologist and professor of medicine at Massachusetts General Hospital and Harvard Medical School in Boston, said the study shows that adults aged 45-49 years have a fairly “comparable prevalence of polyps at higher risk of becoming colorectal cancer to adults aged 50-59 years.”
He noted that recent data, including a study from his group reported previously by Medscape Medical News, also showed that starting screening at an earlier age resulted in substantial benefits to younger individuals.
“Taken together, these studies support recent recommendations to lower the age of initiation of screening to age 45,” Chan said.
“There remains a need for data to understand the acceptability and uptake of screening among younger individuals, including comparisons of more noninvasive screening modalities, such as stool-based testing, with colonoscopy,” he said.
Funding for this study was provided by grants from the ReMission Foundation and the National Cancer Institute. Liang has received research support from Epigenomics and Freenome. Chan has received grants from Pfizer Inc, and personal fees from Pfizer Inc, Bayer Pharma AG, and Boehringer Ingelheim.
Gastroenterology. Published online May 25, 2022. Abstract