Global study reveals alarming rise in early-onset colorectal cancer
Early-onset colorectal cancer incidence rates are increasing in more than half of the countries studied worldwide, with the steepest rises seen in New Zealand, Chile, and Puerto Rico, according to comprehensive new research published in The Lancet Oncology [1].
The landmark study, led by American Cancer Society researchers, analysed data from 50 countries and territories, examining colorectal cancer trends in younger adults (aged 25-49 years) versus older adults (50-74 years). The research represents the most extensive analysis of its kind, incorporating data through 2017 from high-quality population-based cancer registries.
Global patterns emerge
“The increase in early-onset colorectal cancer is a global phenomenon,” said Dr Hyuna Sung, senior principal scientist at the American Cancer Society and lead author. “Previous studies have shown this rise in predominately high-income Western countries, but now, it is documented in various economies and regions worldwide.”
The analysis revealed that early-onset colorectal cancer incidence rates increased in 27 of 50 countries during the past decade, with the most significant annual increases occurring in:
- New Zealand (4.0%)
- Chile (4.0%)
- Puerto Rico (3.8%)
- England (3.6%)
Contrasting trends between age groups
In 14 countries, including the United States, rates increased in young adults while stabilising or decreasing in those aged 50 and older. This divergent pattern was particularly evident in high-income Western nations, where screening programmes have helped reduce incidence in older populations.
Geographic and demographic variations
The study identified distinct regional patterns. While the increase was initially observed primarily in high-income Western countries, it has now extended to nations in Latin America, Asia, and eastern Europe. The authors note that these trends often coincide with economic development and lifestyle changes.
Gender differences emerged in several countries. The rise in early-onset cases was more rapid among men in countries including Chile, Puerto Rico, and Argentina, while women experienced faster increases in England, Norway, and Australia.
Current incidence rates
For the most recent five-year period studied, the highest incidence rates of early-onset colorectal cancer were found in:
- Australia (16.5 per 100,000)
- Puerto Rico (15.2 per 100,000)
- New Zealand (14.8 per 100,000)
- United States (14.8 per 100,000)
- South Korea (14.3 per 100,000)
The lowest rates were observed in Uganda and India (approximately 4 per 100,000).
Awareness of key symptoms
The researchers emphasise that while screening programmes have helped reduce colorectal cancer rates in older adults, different strategies may be needed for younger populations. The study authors note that raising awareness of early-onset colorectal cancer symptoms among young people and healthcare providers is crucial for early detection.
According to the paper, key symptoms that warrant attention include rectal bleeding, abdominal pain, altered bowel habits, and unexplained weight loss.
Future research directions
The authors highlight the need for further investigation into the causes of these trends, particularly focusing on modifiable risk factors during early life. They suggest that changes in dietary habits, physical activity levels, and obesity rates may play significant roles, though the specific drivers likely vary across different populations and regions.
The study’s findings underscore the urgent need for global initiatives and cross-country partnerships to identify causes and implement effective preventive strategies aligned with local resources and cultural contexts.
Reference:
- Sung, H., Siegel, R. L., Laversanne, M., et. al. (2024). Colorectal cancer incidence trends in younger versus older adults: an analysis of population-based cancer registry data. The Lancet Oncology. Published online December 11, 2024. https://doi.org/10.1016/S1470-2045(24)00600-4
