Early-Onset Colorectal Cancer on the Rise in Whites, Stable in Blacks

Rates of early-onset colorectal adenocarcinoma increased among the white U.S. population over the past 2 decades, approaching rates in the Black population, which remained stable, a cross-sectional study revealed.

For individuals ages 40 to 49, the rate of colorectal adenocarcinoma in the white population increased from 19.6 to 25.2 per 100,000 person-years from 2000 to 2017, for an annual percent change (APC) of 1.6 (95% CI 1.3-1.9). In the Black population, rates changed from 26.4 to 25.8 per 100,000 person-years over the study period, a non-significant dip, reported Jordan J. Karlitz, MD, of the University of Colorado School of Medicine in Denver, and colleagues.

Among white women, rectal adenocarcinoma specifically increased over the study period (APC 2.2, 95% CI 1.6-2.8), as compared to a non-significant drop among Black women (APC -1.7, 95% CI -3.6 to 0.3).

“Our analysis is the first to find that white women may be a significant driver of overall increases in rectal cancer rates,” the group wrote in JAMA Network Open, citing obesity as a significant contributing factor to early-onset disease.

Overall, the absolute rectal adenocarcinoma incidence rate was 39% lower among the Black population as of 2017, the authors noted, with a possible contributing factor including the early “introduction of a screening threshold of age 45 years in Black individuals.”

In 2008, the American College of Gastroenterology (ACG) issued recommendations encouraging colorectal cancer screening for Black people at average risk starting at age 45. In 2018, the American Cancer Society recommended screening starting at this earlier age for all individuals — ACG followed suit in 2021, though the recommendation was “conditional” due to low-quality evidence.

With the shift in guidelines, “these data can help motivate real-world implementation of guidelines to maximize screening rates that have historically been suboptimal in younger individuals,” the authors argued.

“Historically, colorectal cancer rates in Black individuals in this age group, and other age groups as well, have been significantly higher than white individuals,” Karlitz told MedPage Today.

“Despite favorable incidence rate trends in many of the 40-49-year-old Black population subgroups, sub-analyses identified a persistent disproportionate high rate of colon cancer in Black women,” he explained. “We need to understand why this is the case so that we can develop potential interventions to counteract this trend.”

Karlitz also cautioned that “individuals who have concerning GI symptoms or a family history of colorectal cancer or other cancers, may not be considered ‘average-risk’ and may need evaluations before age 45.”

For their study, the researchers evaluated the Surveillance, Epidemiology, and End Result (SEER) 18 database on 45,429 individuals ages 40-49 years who were diagnosed with colorectal adenocarcinoma from 2000 to 2017. In total, 46,728 colorectal cancers were identified among these patients.

The primary outcome assessed early-onset colorectal cancer incidence, including the APC and annual rate ratios, stratified based on sex, age, anatomic subsite (colon-only/rectal-only), and adenocarcinoma histology.

White patients made up 60% of the cohort while Black patients made up 14%. Average age at diagnosis was 45.5. Among the white population, 12,776 cases were in women and 15,443 were in men. For the Black population, 3,282 cases were in women and 3,371 were in men.

The analysis had several limitations, the researchers acknowledged, including the exclusion of other races and ethnicities. Also, the observational nature of the data also prevented the ability to collect information on factors that may have influenced the results, such as screening access.