Colorectal cancer screening rising in younger populations
Three new studies looked at the rates, types, and results of colorectal cancer screening in patients ages 45 to 49 years in recent years.
Three studies published Aug. 4 by JAMA looked at colorectal cancer (CRC) screening in younger populations.
The first study, conducted in one large health system, randomized 20,509 primary care patients ages 45 to 49 years who were at average risk for colorectal cancer to four outreach strategies: fecal immunochemical test (FIT)-only active choice, colonoscopy-only active choice, dual-modality (FIT or colonoscopy) active choice, and usual care default mailed FIT. The primary outcome was participation in screening (FIT or colonoscopy) at six months, while the secondary outcome was the screening modality used.
Participation was significantly lower among the three active-choice groups (FIT only, 16.4%; colonoscopy only, 14.5%; dual-modality FIT or colonoscopy, 17.4%) compared to the usual care default mailed FIT group (26.2%; P <0.001 for all comparisons). Participants who were offered dual-modality active choice were more likely to complete any screening than those offered a single active choice (17.4% [dual-modality FIT or colonoscopy] vs. 15.4% [FIT only and colonoscopy only combined]; rate difference, −1.8% [95% CI, −3.0% to −0.1%]; P=0.004]). Among the 5,125 participants offered a choice between two modalities, colonoscopy was more commonly chosen than FIT (12.0% vs. 5.6%; rate difference, −6.4% [95% CI, −7.5% to −5.3%]; P<0.001).
A research letter noted that the recommended age to begin CRC screening was lowered from 50 years to 45 years by the American Cancer Society in 2018 and the U.S. Preventive Services Task Force in 2021. To determine whether observed increases in CRC incidence reflected earlier detection through screening or increasing disease rates, researchers looked at CRC cases diagnosed from 2004 to 2022 among adults ages 20 to 54 years. Cases were stratified by age, anatomic subsite, and stage at diagnosis. There were 219,373 cases (men, 119,877; women, 99,496; mean age, 46.9 years).
Among those ages 45 to 49 years, there was an increase of 1.1% (95% CI, 0.3% to 1.6%) in annual incidence from 2004 to 2019 and 12.0% (95% CI, 6.5% to 14.6%) during 2019 to 2022. This steep increase was driven by local-stage tumors (annual percentage change [APC], 21.8%; 95% CI, 13.8% to 26.2%), which increased from 9.4 per 100,000 in 2019 to 11.7 per 100,000 in 2021, a 25% relative increase, and to 17.5 per 100,000 in 2022, a 50% increase relative to 2021. Local-stage diagnoses increased similarly during 2019 to 2022 for colon cancer (APC, 18.8%; 95% CI, 6.9% to 25.3%) after previously stable rates and for rectal cancer (APC, 25.1%; 95% CI, 17.8% to 29.3%) after a declining trend.
The study results contrast with consistent increases of distant-stage diagnoses and likely reflect diagnosis of prevalent asymptomatic cancer through first-time screening, the study authors said. Also, the sudden uptick in incidence among adults ages 45 to 49 years in 2021 may reflect a rebound of missed diagnoses in 2020 because of pandemic-related disruptions.
Finally, another research letter reported a cross-sectional trend analysis of data from the National Health Interview Survey. Among patients ages 45 to 49 years, CRC screening prevalence increased from 20.8% in 2019 and 19.7% in 2021 to 33.7% in 2023, colonoscopy prevalence increased from 19.5% in 2019 and 17.8% in 2021 to 27.7% in 2023, and stool-based testing increased from 1.3% in 2019 and 2.7% in 2021 to 7.1% in 2023. Screening remained mostly stable for all other age groups.
The researchers wrote that this trend is encouraging because screening reduces CRC mortality and screening for adults ages 50 to 75 years remained largely stable, suggesting no reduced access for older individuals.
An editorial associated with all three studies concluded, “Existing, evidence-based interventions such as a mailed FIT effectively increase screening participation among younger adults, and expanding eligibility to younger adults does not diminish participation among older adults. Examining trends in incidence rates and stage at diagnosis can provide insight into whether screening translates into earlier detection of asymptomatic cancers.”