University of Texas Southwestern Medical Center Dallas, TX, United States
Timothy A. Zaki, MD1, Amit G. Singal, MD, MS1, Folasade May, MD, PhD2, Caitlin C. Murphy, PhD, MPH3 1University of Texas Southwestern Medical Center, Dallas, TX; 2University of California Los Angeles David Geffen School of Medicine, Los Angeles, CA; 3University of Texas Health Science Center at Houston, Houston, TX
Introduction: Incidence rates of early-onset colorectal cancer (CRC, age < 50 years) have increased successively across generations or birth cohorts. As generations mature, they will carry with them an elevated risk of CRC, raising the possibility that incidence rates will begin to increase at older ages, such as persons older than age 50 years. To test this hypothesis, we examined temporal trends in incidence rates for ages 45-49, 50-54, and 55-59 years in a population-based sample.
Methods: We used National Cancer Institute’s Surveillance, Epidemiology, and End Results (SEER) program data to estimate age-adjusted and age-specific (45-49, 50-54, and 55-59 years) incidence rates per 100,000 persons during the period 1992–2018 in approximate 4-year intervals. To account for the possibility that incidence rates may increase due to increasing uptake of CRC screening, we estimated age-specific incidence rates by stage at diagnosis, as well as prevalence of CRC screening using data from the Behavioral Risk Factor Surveillance System.
Results: Between 1992-95 and 2016-18, incidence rates increased from 23.4 to 34.0 per 100,000 persons for age 45-49 years and from 46.4 to 63.8 per 100,000 persons for age 50-54 years (Figure 1). Conversely, incidence rates decreased during the same period for the 55-59-year age group, from 81.7 to 63.7 per 100,000 persons. Because of this opposing trend—or decreasing rates for age 55-59 years and increasing rates for age 50-54 years—incidence rates for the two age groups were nearly identical in 2016-18. For ages 45-49 and 50-54 years, incidence rates of local, regional, and distant disease increased from 1992-95 to 2016-18; however, rates decreased for the 55-59-year age group. Prevalence of endoscopy increased for ages 50-54 and 55-59 years from 2004 to 2018, and prevalence of stool blood tests decreased.
Discussion: We observed a clear pattern of increasing incidence rates of CRC—across all stages—for adults in their early 50s, supporting our hypothesis that incidence rates will increase at older ages as higher-risk generations mature. These increases have not been previously well-described and do not appear to be solely driven by earlier detection via screening. Rather, increasing rates of CRC for age 50-54 years parallel increases in early-onset CRC, and the same, as-yet-unknown mechanisms contributing to increasing incidence rates at ages younger than 50 years may also contribute to increasing rates in this age group.
Figure: Figure 1. Age-specific incidence rates of colorectal cancer (n=101,609 diagnoses in persons age 45-59 years), by four-year interval, SEER 13, 1992-2018
Timothy Zaki indicated no relevant financial relationships.
Amit Singal indicated no relevant financial relationships.
Folasade May indicated no relevant financial relationships.
Caitlin Murphy: Freenome – Consultant.
Timothy A. Zaki, MD1, Amit G. Singal, MD, MS1, Folasade May, MD, PhD2, Caitlin C. Murphy, PhD, MPH3. P0281 - Increasing Incidence Rates of Colorectal Cancer in Adults After Age 50, ACG 2021 Annual Scientific Meeting Abstracts. Las Vegas, Nevada: American College of Gastroenterology.