Introduction: The United States Preventive Services Taskforce lowered the recommended starting age for colorectal cancer (CRC) screening in average-risk adults from 50 to 45 years due to a rapid increase in young CRC incidence and overall favorable benefit-to-burden ratio in the US. This recommendation has not been widely adopted by other countries partially because the burden of young CRC in these countries is unclear compared to the United States.
Methods: The incidence rates of early-onset CRC in young adults (defined as the onset of CRC in individuals aged between 20 to 49 years) from 1990 to 2019 were collected from the Global Health Data Exchange (GHDx) results tool (available at https://vizhub.healthdata.org/gbd-results). Data from 204 countries and geographic areas were available. The socio-demographic index (SDI) was used to categorize countries and geographic areas by development (low, low-middle, middle, high-middle, and high).
Results: The global incidence rate of young CRC increased from 4.2/100,000 to 6.7/100,000 from 1990 to 2019, with an annual percentage change (APC) of 1.6%. The increase in CRC incidence rate was faster in young adults than in individuals aged 50-74 years (APC 0.6%). In the high HDI region, the CRC incidence rate decreased in adults aged 50-74 years old while it increased in adults 20-49 years old from 1995 to 2019 (Table). The increase in young CRC incidence rate was consistently observed in all five SDI regions and 185 out of 204 countries and territories (Figure a). Middle (120.8%), high-middle (98.5%), and low-middle (63.7%) SDI regions experienced the most rapid increase in young CRC incidence rate, while the high SDI region had the highest incidence rate by 2019 (11.5 per 100,000). By 2019, nine countries and territories (Taiwan, Monaco, Portugal, Andorra, Japan, China, Bulgaria, Hungary, and Slovakia) had higher young CRC incidence rates than the United States (Figure b); CRC screening for average-risk adults aged 45-49 years should be studied in these countries. A concerning 142 countries had a higher annual percentage increase of young CRC than the United States, which warrants further attention and investigation.
Discussion: The global incidence, mortality, and DALYs of young CRC increased from 1990 to 2019. The increase in young CRC incidence was prevalent in most countries worldwide. Several countries were found to have higher incidence rates or faster increase in young CRC, which warrants further attention.