Lower Colorectal Cancer Screening Initiation Age Has Not Decreased Lesion Detection Rates

Colorectal cancer,medical anatomical illustration.
Given the updated guidelines for younger initiation age, researchers assessed the effect on screening colonoscopy volume in patients aged 45 to 49 years and lesion detection rates.

Lowering the initiation age for colorectal cancer (CRC) screening has had a modest effect on colonoscopy volume by age, with lesion detection rates among individuals aged 45 to 49 years similar to those aged 50 to 54 years at initial screening, according to a study recently published in Clinical Gastroenterology and Hepatology.

Researchers examined 7990 screening colonoscopies, 3724 of which were rescreenings, and 4266 of which were initial screenings. All screenings, performed by endoscopists, occurred during 2 periods: period 1 (October 2017 to December 2018) and period 2 (January 2019 to August 2021), the latter of which took place under new guidelines. Those undergoing colonoscopies in periods 1 and 2 had a similar median age (57 vs. 56 years, respectively) and percentage of women (53.2% vs. 53.3%, respectively). Colonoscopy volumes and lesion detection rates were compared between the 2 periods.

An increase was observed in the percentage of initial screenings among individuals aged 45 to 49 years between periods 1 and 2 (3.5% to 11.6%; relative risk, 3.36; 95% CI, 2.45-4.61). During both periods, most initial screenings took place among individuals aged 50 to 54 years. However, rescreening colonoscopies shifted to older age groups, with most occurring among individuals aged 60 to 64 years (24.8% and 26.1% in periods 1 and 2, respectively). In period 2, patients aged 45 to 49 years, 50 to 54 years, and 60 to 64 years had similar respective detection rates for adenoma (34.3% vs 38.2% vs 33.4%), advanced adenoma (6.3% vs 5.8% vs 6.1%), sessile serrated lesion (8.6% vs 9.4% vs 7.2%), advanced sessile serrated lesion (2.9% vs 3.0% vs 2.3%), adenomas per colonoscopy (0.58 vs 0.63 vs 0.61), and lesions per colonoscopy (0.69 vs 0.76 vs 0.70). There were increases in detection rates, adenomas per colonoscopy, and lesions per colonoscopy between periods 1 and 2, with no decreases among individuals aged 45 to 49 years.

Study limitations included a potential lack of generalizability, an inability to detect CRC diagnosis, a relatively small sample size, a lack of demographic information beyond age and sex, and an inability to independently validate the accuracy of the listed indications for colonoscopy.

“…[S]creening colonoscopy volume among patients [aged 45 to 49 years] has increased modestly, and lesion detection rates in patients [aged 45 to 49 years] have not decreased as might have been seen if low-risk persons were self-selecting for screening,” the study authors noted. “Lesion detection rates among patients [aged 45 to 49 years] were only slightly lower than, but comparable to, those among patients [aged 50 to 54 years] at first-time screening, and virtually the same as those among  patients [aged 60 to 64 years] at rescreening colonoscopy.”

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


Ladabaum U, Shepard J, Mannalithara A. Adenoma and sessile serrated lesion detection rates at screening colonoscopy for ages 45-49 years vs. older ages since the introduction of new colorectal cancer screening guidelines. Clin Gastroenterol Hepatol. Published online May 14, 2022. doi:10.1016/j.cgh.2022.04.037