When it comes to the incidence of colorectal cancers, there is some good news. Cancers of the colon and rectum have been declining in older adults in recent decades, possibly because of better awareness of the importance of initial screening at age 50. However in a new study conducted by the American Cancer Society that looked at colorectal cancer incidence by age group, rates have been increasing for every generation born since 1950. People born in 1990 have double the risk of developing colon cancer and quadruple the risk of developing rectal cancer. While the numbers of these cases are comparatively small, the upward trend is still quite worrisome.
The ACA study examined the records of nearly 500,000 people 20 years and older who were diagnosed with colon or rectal cancer from 1974 through 2013, with data from the Surveillance, Epidemiology and End Results (EER) program registries of people with cancer.
The ACA reported that through 2013, rates of colon cancer increased by 1% to 2% for adults 20 – 39, and increased by 0.5% to 1% per year in adults 40 – 54, from the mid-1990s. And rectal cancer incidence rates have been increasing even longer and faster than colon cancer, rising about 3% per year from 1974 to 2013 in adults ages 20 to 29 and from 1980 to 2013 in adults ages 30 to 39. In adults ages 40 to 54, rectal cancer rates increased by 2% per year from the 1990s to 2013.
We don’t know why the rates of colon and rectal cancer are rising in younger adults, but some of the “usual suspects” are obesity and sedentary lifestyles, as well as alcohol use and chronic conditions like inflammatory bowel disease and type 2 diabetes. And, we know that a Western diet is problematic for all of these conditions. In one study, people from Africa who were suddenly switched to an American diet had signs of inflammation in their colons within just two weeks.
To complicate the issue, younger people with colorectal cancer run the risk of being diagnosed later in the course of the disease when it may be more difficult to treat. Unfortunately, symptoms of colorectal cancer are typically vague and include general digestive complaints like diarrhea or constipation, cramping and abdominal pain. These complaints may be overlooked as warning signs of cancer in young people because the vast majority of colon and rectal cancers (nearly 90 percent) are found in adults over 50.
An important message to learn from the study is that young people can and do get colon and rectal cancer, so they should pay attention to the signs and symptoms, and so should their doctors.
According to Rebecca Siegel, MPH, Strategic Director of Surveillance information Services in the Intramural Research Department at the American Cancer Society, health care providers should educate young patients about healthy lifestyle behaviors, and patients should be aware of the symptoms of colorectal cancer and report any changes to their physician. The most common signs and symptoms include:
At this time the American Cancer Society has not announced any changes to screening guidelines for colorectal cancer, but the new data will be examined by the organization’s independent guidelines development group to review whether a change is warranted, particularly since screening may help prevent colorectal cancer or diagnose it sooner and reduce the number of related deaths among adults in the most productive years of life.
Currently, the American Cancer Society recommends testing starting at age 50 for most people, with screening starting at a younger age for those with a family history of colon or rectal cancer.
Special thanks to Reed B. Hogan, II, M.D., of GI Associates in Madison and Flowood, MS, for editorial review and assistance with the preparation of this article. Dr. Hogan is board certified in Gastroenterology and Internal Medicine.