Colorectal cancer is one of the most preventable cancers, yet it remains the third most common cancer among US men and women.
The good news is that rates have declined 30 percent among people 50 years of age and older, however incidence and mortality among individuals under 50 are on the rise and expected to climb. Among 20-34 year olds, rates of colorectal cancer have increased 51% since 1994 and in the period from 2010-2030, colorectal cancer in this age group is expected to increase by 90 percent.
At the Early Age Colorectal Cancer Onset Summit last week, I was one of the speakers talking about the concerning increase in this cancer among adults in their 20s through 40s.
Among 20-34 year olds, rates of colorectal cancer have increased 51% since 1994 – and in the period from 2010-2030, colorectal cancer in this age group is expected to increase by 90%.
Alarmingly, cancers in the under 50 population are diagnosed at later stages (most often due to delays in diagnosis) and appear to be more aggressive tumor types, both of which have implications for prognosis and survival.
What’s unknown is the cause of young onset colorectal cancer.
What we do know, is that more than 50% of colorectal cancer cases can be prevented through lifestyle – by eating a healthy diet, maintaining a healthy body weight, engaging in regular physical activity, and reducing sedentary time.
However, few epidemiological studies have investigated risk factors specifically in the under 50 population. Current evidence suggests obesity is related to young onset colorectal cancer.
Studies that have investigated various risk factors associated with young onset colorectal cancer have found numerous dietary factors associated with decreased risk. These include vegetables, citrus fruits, fish intake, and intake of the following nutrients beta-carotene (found in orange and yellow pigmented fruits and vegetables such as carrots and squash), folate (found in dark green leafy vegetables, especially spinach and kale), vitamin C (found in strawberries and citrus fruits), and vitamin E (found in whole grains, especially wheat germ).
These studies also identified that both alcohol intake – greater than or equal to 2 drinks per day – and high consumption of processed red meat increased the risk of colorectal cancer under 50. We still don’t fully understand the timing of these exposures in the carcinogenesis process or the duration of time that an individual should be exposed to these factors to increase or decrease their risk.
But, these initial studies are promising and support risk factor research in the over 50 population that points to a significant contribution of lifestyle factors impacting risk for this disease in the young population.
For more information on factors related to reducing colorectal cancer risk, here’s the latest AICR/WCRF analysis of the evidence.
Christine L. Sardo Molmenti, PhD, MPH, RD, is AICR’s Science Analyst. Chris is a cancer epidemiologist at Columbia University’s Mailman School of Public Health and specializes in making the science of cancer prevention understandable, and doable. You can connect with her on twitter @christinesardo.