While rates of colorectal cancer (CRC) in the United States are declining due to improved screening in older adults, it has been reported that rates are on the rise among younger adults. It is not known if this trend is specific to the United States or if it is occurring globally. In order to examine this question, a study published this month in Gut evaluated long-term data on CRC incidence from a global database of 43 countries on 6 continents from 2008 to 2012 to determine the relationship between patient age, nationality, and rate of CRC.
Incidence of CRC in patients under the age of 50 varied between countries. Lowest rates were observed in India, where the incidence was 3.5 cases per 100,000 patients. Highest rates were found in Korea, where the incidence was as high as 12.9 cases per 100,000 patients. Among the 36 countries with enough CRC cases to be included in the study, 19 countries experienced increasing rates of CRC among younger adults during the study period. These included primarily high-income countries, including the United States. South Korea and New Zealand had the fastest rate of increase, with an average annual percent change of 4.2 and 4.0, respectively. In Cyprus, the Netherlands, and Norway, the increase in rates of CRC among young adults was double that seen in adults over 50. Incidence of CRC among young adults was stable in 14 countries, while rates decreased in Austria, Italy, and Lithuania.
The investigators concluded that rates of CRC are rising among young adults in high-income countries worldwide, though the cause of this increase is not clear. More careful assessment for cancer risk in young people, particularly in those with a familial history of cancer, should be considered in order to aid in early detection and treatment. Furthermore, additional studies will be needed to evaluate potential causes of this increase, including the relationship between early-life exposures and CRC.
Visit Medscape Oncology to learn more about this study.