The incidence of colorectal cancer (CRC) is rising in Europe among people aged 20–49 years and if this trend continues we might need to reconsider screening guidelines to include 45-50 year olds, researchers have warned. Their study*, covering 20 countries and published today in Gut, showed that the fastest rise is occurring in the youngest age group, and the rise is more prominent for colon cancer than for rectal cancer; but the rise in incidence has not been associated with a similar rise in mortality.
The research team, from Erasmus MC University Medical Centre in Rotterdam, Netherlands, pointed out that CRC incidence among people aged 50 and more is in decline; and in response to an increase in CRC incidence among 20-40 year olds in north America, Australia and China, the American Cancer Society recently recommended lowering the age to start screening from 50 to 45 years. But, they said, we have lacked data on CRC incidence among younger adults in Europe – so they analysed European trends in CRC incidence and mortality in the under-50s.
They retrieved data on age-related CRC incidence and mortality for 1990-2016 from 20 European countries’ national and regional cancer registries, covering a total of 143.7 million people aged 20–49 years, which they analysed and expressed as annual percent change.
They reported that 187,918 (0.13%) of subjects were diagnosed with CRC and that, on average, CRC incidence increased by 7.9% per year among subjects aged 20-29 years from 2004 to 2016. The overall increase in CRC incidence among 30-39 year olds was 4.9% per year from 2005 to 2016, while the increase in 40-49 year olds was 1.6% per year from 2004 to 2016. They added that CRC mortality did not significantly change among the youngest adults, but decreased by 1.1% per year between 1990 and 2016, and 2.4% per year between 1990 and 2009, among those aged 30-39 years and 40-49 years, respectively.
However, this was not consistent across Europe. CRC incidence increased significantly among subjects aged 20–39 years in 13 countries: Belgium, Germany, the Netherlands, the UK, Norway, Sweden, Finland, Ireland, France, Denmark, Czech Republic and Poland, while Italy showed a decrease in incidence in this age group and there was no significant change in the remaining six countries. CRC incidence increased significantly among subjects aged 40–49 years in eight countries: the UK, Greenland, Sweden, Slovenia, Germany, Finland, Denmark and the Netherlands, while only Czech Republic showed a significant decrease in incidence from 1997 to 2015 and there was no significant change in the remaining 11 countries.
The study authors said as their study was purely observational it could not establish cause, and it was also limited by variation in data quality between countries, but they suggested that the rise in obesity, alcohol intake and smoking and declining physical activity might be reasons for the trends. They added that although it is still too early to use their data to support screening in Europe for those aged 45-50 years, we should monitor this trend and keep assessing whether screening guidelines need to be reconsidered.
They concluded: “Furthermore, we should find underlying causes, and identify high-risk subjects who might benefit from earlier screening. A first step to reach this goal is to make clinicians aware that the CRC incidence in young adults is rising quite rapidly.”
*Vuik FE, Nieuwenburg SA, Bardou M, et al. Increasing incidence of colorectal cancer in young adults in Europe over the last 25 years. Gut. Published Online First: 16 May 2019. doi: 10.1136/gutjnl-2018-317592