In 2020, nearly 150,000 Americans, mostly those aged 50 and older, were diagnosed with colorectal cancer. However, about 18,000 of those individuals were younger than age 50. And while colorectal cancer rates have decreased for people over age 50, they have been increasing by 51% since 1994 for those under age 50, prompting both the American Cancer Society and the U.S. Preventive Services Task Force to recommend colorectal cancer screenings begin at age 45 for people at average risk, instead of age 50.

A study investigating the colorectal cancer screening patterns of those aged 50 to 54—adults who were once the youngest age group eligible for screening—to better understand the potential pitfalls now that screening has been expanded to include those aged 45 to 49 has found that the prevalence of colorectal cancer screening remains low for individuals aged 50 to 54. These younger adults also faced higher screening disparities based on race, ethnicity, household income, educational attainment, and insurance coverage. The study was published by Liu et al in Cancer Epidemiology, Biomarkers & Prevention.

Study Methodology

The researchers analyzed data from the National Health Interview Survey from the years 2000, 2003, 2005, 2008, 2010, 2013, 2015, and 2018 to estimate the prevalence of colorectal cancer screening by colonoscopy, sigmoidoscopy, computed tomography colonography, or stool-based tests in a population sample of 80,220 patients between the ages of 50 and 75. The researchers excluded participants with a personal history of colorectal cancer and with missing information on colorectal cancer screening.

For each survey year, the researchers estimated prevalence by age, race/ethnicity, educational attainment, family income, and health insurance. They also compared increases in prevalence of screening from 2000 to 2018 in 5-year age groups, including age 50 to 54, 55 to 59, 60 to 64, 65 to 69, and 70 to 75 years.

Results

The researchers found that, overall, colorectal cancer screening prevalence increased from 36.7% in 2000 to 66.1% in 2018. It was lowest, in 2018, for those aged 50 to 54 years (47%), Hispanic patients (56.5%), Asian patients (57.1%), participants with less than a high school degree (53.6%), those from low-income families (56.6%), or those without health insurance (39.7%).

Increases in prevalence over time differed by 5-year age group. For example, prevalence increased from 28.2% in 2000 to 47.6% in 2018 (+19.4%, 95% confidence interval [CI] = 13.1%–25.6%) for ages 50 to 54, but from 46.4% to 78.0% (+31.6%, 95% CI = 25.4%–37.7%) for ages 70 to 75. This pattern was consistent across race/ethnicity, educational attainment, family income, and health insurance.

“Prevalence of colorectal cancer screening remains low in adults ages 50 to 54 years,” concluded the study authors.

Clinical Significance

“Across all age groups, colorectal cancer screening participation remains below national goals, and the benefits of screening are not equally realized across populations,” said principal investigator of the study Caitlin C. Murphy, PhD, MPH, Associate Professor at The University of Texas Health School of Public Health in Houston, in a statement. “Extra care must be taken to ensure that expanding screening to younger ages does not negatively impact efforts to eliminate disparities in colorectal screening and outcomes, nor jeopardize efforts to increase screening initiation among older adults who remain unscreened.”

Disclosure: Funding for this study was provided by the National Institutes of Health and the Cancer Prevention and Research Institute of Texas. For full disclosures of the study authors, visit aacrjournals.org/cebp.