It has been widely reported that colorectal cancer incidence has been increasing among younger adults under age 50 since the mid-1990s, with a consistent annual increase of 2% among adults aged 20 to 39. This increase prompted the American Cancer Society (ACS), in 2018, and the United States Preventive Services Task Force, in 2021, to recommend lowering the age for colorectal cancer screening from 50 to 45 years for individuals at average risk of developing the disease.
According to a pair of new studies by the ACS, increases in colorectal cancer screening in adults aged 45 to 49 are resulting in rises in earlier-stage diagnosis—12% per year from 2019 to 2022, up from 1.1% annually from 2004 to 2019. The findings are linked to lowering the age to begin recommended colorectal cancer screening from 50 to 45 years, which increased screenings among those aged 45 to 49 by 62% from 2019 to 2023. However, whether the data reflect earlier detection through screening or increased disease occurrence is unknown. The studies by Star et al and Schafer et al are published in the Journal of the American Medical Association.
Study Methodology
For the study by Star et al, researchers analyzed data from more than 53,000 participants in the National Health Interview Survey comparing changes in colorectal cancer screening from 2019 to 2023 within age groups of 40 to 44, 45 to 49, 50 to 54, 55 to 64, and 65 to 75 years. The data were adjusted for age, sex, race/ethnicity, education, and region. Multitargeted DNA stool testing was restricted to individuals who had ever received a fecal occult blood test (FOBT) or fecal immunochemical test (FIT) to ensure consistency with questions in the 2019 survey for accurate comparison. When unrestricted by ever FOBT/FIT status, up-to-date colorectal cancer screening was 20% in 2021 and 37% in 2023. All analyses in this study were conducted in SAS-callable SUDAAN version 9.4 (SAS Institute).
For the study by Schafer et al, investigators reviewed colorectal cancer incidence data from over 219,300 adults (119,877 men and 99,496 women) aged 20 to 54 years taken from 21 registries of the Surveillance, Epidemiology, and End Results (SEER) Program from 2004 to 2022. Individuals were stratified by age; cancer location, either the colon or rectum; and stage at diagnosis. Incidence rates, adjusted for delays in cancer reporting and age-standardized to the 2000 U.S. standard population, were calculated using SEER Stat version 8.4.4 (National Cancer Institute).
- Increases in colorectal cancer screening in adults aged 45 to 49 are resulting in rises in earlier-stage diagnosis—12% per year from 2019 to 2022, up from 1.1% annually from 2004 to 2019.
- The findings are linked to lowering the age to begin recommended colorectal cancer screening from 50 to 45 years, which increased screenings among those aged 45 to 49 by 62% from 2019 to 2023.
Results
According to the Schafer et al analysis, colorectal cancer incidence increased steadily by 1.6% annually since 2004 among adults 20 to 39 years and by 2.0% to 2.6% annually since 2012 among adults 40 to 44 and 50 to 54 years. However, in individuals 45 to 49 years, a previous increase of 1.1% per year during 2004 to 2019 accelerated to 12.0% per year from 2019 to 2022. This steep increase, according to the study findings, was driven by the detection of local-stage tumors, which increased from 2019 to 2022 by 18.8% annually for colon cancer after previously stable rates of localized disease among adults 20 to 39 years and slower increases of 2.5% to 3.1% annually among those aged 40 to 44 and 50 to 54 from 2016 to 2017 that were confined to rectal tumors.
The researchers also found that cases advanced-stage colorectal cancer continued to increase sharply by 1.7% to 2.9% annually since 2004 among those under age 45, and more steeply during the past decade in those aged 45 to 54.
“These findings contrast with consistent increases of distant-stage diagnoses in this age group [45 to 49], said lead author Elizabeth J. Schafer, MPH, Associate Scientist, Surveillance and Health Equity Science at the ACS, in a statement. “It is promising news because the uptick of cases is likely due to first-time screening in the wake of new recommendations for younger average-risk adults to begin testing for colorectal cancer earlier.”
The results for the Star et al study showed that colonoscopy screening among those aged 45 to 49 increased by 43%, and stool-based testing increased more than fivefold from 2019 to 2023. Screening also increased significantly during those years in every racial and ethnic group, but remained unchanged among individuals with less than a high school education and those who were uninsured. Across survey years, according to the results, individuals aged 45 to 49 were primarily White and privately insured.
“It’s not only thrilling to see the increase in colorectal cancer screening among younger adults, but also how it likely ties into rises in earlier-stage diagnosis as noted in the [Schafer et al] paper,” said lead author Jessica Star, MPH, MA, Associate Scientist, Cancer Risk Factors and Screening Surveillance Research at the ACS, in a statement. “However, we still have a long way to go. Screening for colorectal cancer in [those aged] 45–49 remains suboptimal and has not increased equitably by both educational attainment and insurance status.”
Disclosures: The study authors have no financial conflicts of interest to disclose.