Current trends in the incidence and mortality of colorectal cancer (CRC) in the United States suggest CRC will become a disease that largely affects young and middle-aged adults, according to a report published in CA: A Cancer Journal for Clinicians.
As the second leading cause of cancer-related death in the United States, and with modifiable risk factors accounting for over 50% of cases and deaths, CRC is largely a preventable disease, explained study author Rebecca L. Siegel, of the American Cancer Society, and colleagues.
According to the investigators, CRC incidence dropped by 3.3% per year from 2011 through 2016 among individuals aged 65 years or older, but the opposite was observed for those aged 50-64 years, with rates increasing by 1% per year. The increase was even greater for those younger than 50 years, with an increase of 2.2% per year.
The CRC incidence from 2012 through 2016 was highest among Alaska Natives (89 cases per 100,000 persons) and lowest among Asian/Pacific Islanders (30 cases per 100,000 persons).
“CRC has been the most commonly diagnosed cancer in Alaska Natives since the early 1970s for reasons that are unknown but may include a higher prevalence of risk factors,” the investigators wrote.
The risk of developing CRC is related to several factors, including obesity, vitamin D deficiency, diabetes, smoking, and other dietary factors, the team further explained.
Among those aged 65 years or older, CRC death rates decreased by 3% per year from 2008 through 2017. For those aged 50-64 years, death rates dropped by 0.6% per year. In contrast, death rates rose by 1.3% per year for those younger than 50 years.
“The uptick in young adults, which is most rapid among non-Hispanic whites (2% per year), began around 2004 and was preceded by declines of 1% to 2% per year since at least 1975,” the investigators wrote.
The reduction in incidence and mortality among older adults is partially attributable to higher uptake of CRC screening. According to recent data, CRC screening rates were lower for those aged 50-64 years compared with individuals aged 65 years and older.
Based on current recommendations from the American Cancer Society, CRC screening should begin at age 45, with some higher-risk patients starting at age 40.
“Progress against CRC can be accelerated by increasing access to guideline-recommended screening and high quality treatment, particularly among Alaska Natives, and elucidating causes for rising incidence in young and middle-aged adults,” the investigators concluded.
The authors disclosed financial affiliations with the American Cancer Society, which funded the study, as well as Array Biopharma, Bayer, RGenix, Tesaro, and Seattle Genetics.
SOURCE: Siegel RL et al. CA Cancer J Clin. 2020 Mar 5. doi: 10.3322/caac.21601.