Colonoscopy Screening Effective in 45- to 49-Year-Olds

Medscape

10-06-2025

Screening colonoscopies in 45- to 49-year-olds yield similar rates of cancer and lesions as in 50- to 54-year-olds, according to a new analysis.
Researchers at Kaiser Permanente Northern California sought to compare yields between the two age groups to assess how a change in guidance in 2021 urging screening in the younger cohort was borne out in a real-world setting.
The researchers published their findings in JAMA , concluding that the results supported screening colonoscopy in 45- to 49-year-olds.
The study compared 4380 individuals aged 45-49 years, with 7651 who were aged 50-54. All of them underwent their first colonoscopy during 2021 to 2024. Thirty-five percent of the younger group and 40% of the older group had any adenoma.
About 4% of each group had an advanced adenoma, 10% had any sessile serrated lesion, a little under 2% had an advanced serrated lesion, and 0.1% in each group had colorectal cancer.
There were no significant differences in neoplasia prevalence between the groups by sex. The authors did note that the study group included more Asian individuals (30%) than in the general population.
Swati G. Patel, MD, MS, associate professor of medicine, at University of Colorado Anschutz Medical Center, Denver, said the Kaiser study is important because its data was aggregated after the US Preventive Services Task Force lowered the screening age in 2021.
The Kaiser research 'validates the initial studies' done to support that recommendation and the 2022 consensus statement by the US Multi-Society Task Force on Colorectal Cancer, which also advocated screening in 45- to 49-year-olds.
Even though the new JAMA study found a similar rate of cancers and precursor lesions as in previous trials, it provides 'reinforcement of the rationale for decreasing the screening age,' Patel, the lead author on the consensus statement, told Medscape Medical News .
The Kaiser research is 'really powerful information,' she said.
'It certainly validates our current guidance to start screening for colorectal cancer at age 45,' said Audrey Calderwood, MD, professor of medicine, Geisel School of Medicine, Dartmouth, New Hampshire.
The Kaiser data provides granular information to share with younger patients who might think that they don't need screening because they are healthy and don't have symptoms, said Calderwood, also director of the Comprehensive Gastroenterology Center at Dartmouth Hitchcock Medical Center.
Colon cancer rates for Americans under age 50 have been steadily rising for the past decade, hitting about 10 cases per 100,000 in 2022, according to the National Cancer Institute (NCI). In 2023, about 73% of eligible 50- to 75-year-olds received colorectal cancer screening based on the most recent guidelines, according to the NCI.
But screening rates in the under-50 age group are much lower. Researchers estimated in a study that only about 34.5% of those aged 45-49 received colorectal cancer screening, which included colonoscopy, stool-based tests, and CT colonography.
Patel said that estimate is 'spot on' in terms of other estimates.
'I think there's a perception that it's a cancer of older adults and that young healthy people don't need to worry about it,' she said, adding that getting the word out to younger Americans is a 'PR challenge,' in part because of squeamishness about discussing anything to do with stool and changes in how they access information.
Calderwood agreed. Younger people 'aren't chatting to their friends about' colon cancer screening the way they might about mammography, said Calderwood.
Both she and Patel noted that educating the public was an ongoing project, but that a physician's recommendation was key.
Patel said she hoped that data provided in the Kaiser study might help 'dismantle the systemic skepticism around decreasing the age recommendation' for screening.
Calderwood and Patel reported having no relevant financial relationships.