A new narrative review has highlighted a significant trend in colorectal cancer (CRC) epidemiology, known as the birth cohort effect. This phenomenon indicates a rising risk of CRC in successive generations, particularly those born after 1960.
Key findings from the review include:
Increasing Incidence in Younger Populations: There’s a notable rise in early-onset colorectal cancer (EOCRC), defined as CRC occurring before age 50. This increase is more pronounced in rectal cancer compared to colon cancer, and in distant-stage diagnoses over local-stage ones.
Generational Trends: Generation X (born 1965-1980) has seen a rise in EOCRC, with incidence rates 1.22 to 1.58 times higher than those born between 1950-1954. Millennials (born 1981-1996) are experiencing even higher rates, up to 2.98 times higher for those born between 1990-1994.
Global Pattern: These trends are observed globally, despite varying population structures, screening programs, and diagnostic strategies.
The review emphasizes the need for heightened awareness and early detection efforts, especially for individuals under 45, and stresses the importance of screening for those aged 45 and older. The increasing incidence of CRC in younger age groups and the shifts in patient demographics (more patients under 60 and from diverse racial and ethnic backgrounds) suggest significant public health implications.
The causes of this birth cohort CRC are believed to be multifactorial, involving demographic, lifestyle, environmental, genetic, and other factors. The review calls for more research to understand these complex etiologies and for health systems and policymakers to ensure access to appropriate care and clinical trials, particularly for rectal cancer treatments.