Researchers from the University of Texas M.D. Anderson Cancer Center in Houston conducted a large retrospective cohort study of colon cancer using the Surveillance, Epidemiology, and End Results registry. Age at diagnosis was analyzed in 15-year intervals starting at the age of 20. Data included all 393,241 patients diagnosed with colon or rectal cancer (CRC) from January 1, 1975 through December 31, 2010.
The overall age-adjusted CRC incidence rate decreased by 0.92% between 1975 and 2010, and there was a steady decline in the incidence of CRC in people age 50 years or older; however, the opposite trend was observed for young adults. For patients aged 20 to 34, the incidence rates of localized, regional, and distant colon and rectal cancers have increased. If the current trends continue, there will be rise in colon cancer incidence among young adults by 2030. The incidence is expected to increase by 90% for individuals who are age 20 to 124% for those who are 34 years old. The researchers concluded that further studies are needed to determine the cause for these trends and identify potential preventive and early detection strategies. They noted that behavioral factors, such as obesity and physical inactivity, may play a role in the increasing incidence of CRC among young people, and the typical modern diet high in red meat and processed foods also may play a role in the rising incidence.
Bailey CE et al. Increasing Disparities in the Age-Related Incidences of Colon and Rectal Cancers in the United States, 1975-2010. JAMA Surg. Published online 11/5/14, doi:10.1001/jamasurg.2014.1756.