Thanks in part to improvements in screening, the rates of new colon and rectal cancer diagnoses have been falling in the United States for people ages 50 and older. But for people under 50, for whom routine screening is not recommended, rates seem to be increasing significantly.
Researchers from The University of Texas MD Anderson Cancer Center looked at data from more than 393,000 people diagnosed with colon or rectal cancer between 1975 through 2010 who are part of the National Cancer Institute’s Surveillance, Epidemiology, and End Results (SEER) registry. Based on current trends, they predict that by 2030 the incidence rates among people ages 20 – 34 years will increase by 90% for colon cancer and by 124.2% for rectal cancer. Among people ages 35 – 49 years, they predict the incidence rates will increase by 27.7% for colon cancer and by 46% for rectal cancer.
"The increasing incidence of colorectal cancer among young adults is concerning and highlights the need to investigate potential causes and external influences such as lack of screening and behavioral factors," say the study’s authors. They note that obesity rates have increased significantly in the United States, and obesity is a major risk factor for colon and rectal cancer.
The study was published in the January 2015 issue of JAMA Surgery.
When to Start Screening
Screening means having a test that looks for cancer or another disease in people who don’t have any symptoms.Some screening tests – such as colonoscopies – can find growths called polyps and remove them before they have a chance to turn into cancer. Other screening tests can find cancer early when it’s easier to treat.
Richard C. Wender, MD, American Cancer Society Chief Cancer Control Officer, says finding the ideal age to start screening is a challenge. “Picking the age to start is a balance where the likelihood of finding the disease outweighs the risks of harm. If you don’t have the disease, there is no way a screen can benefit you. Although the harms of colon cancer screening tend to be small, when you’re screening millions of people, you’re going to have more harms.”
He says the American Cancer Society is in the process of updating the guidelines for colon and rectal cancer screening, and is looking at all the numbers.
The benefits of screening tests must be weighed against any risks of the tests themselves. Risks may include anxiety, pain, or other side effects. And screening isn’t perfect. Sometimes screening misses cancer, and sometimes it finds something suspicious that turns out to be harmless, but must be checked out through additional tests that also carry risks.
This is why the American Cancer Society uses scientific evidence to create guidelines for cancer screening. The Society recommends colon cancer screening begin at age 50 for people at average risk. But some people have certainrisk factors that make them more likely to develop it, and to get it at an earlier age. This may mean they should start screening earlier, or get tested more often than other people.
Doctors' Advice to Young Adults
Dr. Wender says there are things young people can do to lower their risk for developing colon and rectal cancer, or to catch it early:
Get to and stay at a healthy weight. Eat a lot of healthy food, mostly vegetables and fruits, and avoid unhealthy foods, especially desserts, snacks, sugar, soda, and other sugary drinks. Eat less red meat (beef, pork, or lamb) and processed meats (hot dogs and some luncheon meats). And be sure to get regular physical activity. You’ll feel better and you may lower your risk for colon cancer, many other cancers, and many other diseases including heart disease and diabetes.
Find out your family history. You may have to do some work to learn who has been diagnosed with colon or rectal cancer, and the age of diagnosis. It’s also important to know if you have a family history of other colon problems that can increase risk. These include pre-cancerous polyps and hereditary syndromes such as familial adenomatous polyposis (FAP) or hereditary non-polyposis colon cancer (HNPCC), also known as Lynch syndrome. Having other conditions, such as ulcerative colitis or Crohn’s disease can also increase your risk of colon cancer. If you have any of these problems, talk to your doctor about when to begin screening.
Take any symptoms seriously. There is no such thing as normal rectal bleeding. If you notice blood, a change in the color or size of your stool, a new pain, or a change in your bowel habits, get checked out by a doctor. Most of the time the cause is not cancer, but it’s important to find out the cause, just in case it is.
Citation: Increasing Disparities in the Age-Related Incidences of Colon and Rectal Cancers in the United States, 1975-2010. Published in the January 2015 issue of JAMA Surgery (Vol. 150, No. 1). First author: Christina E. Bailey, MD, MSCI, University of Texas MD Anderson Cancer Center, Houston.
Reviewed by: Members of the ACS Medical Content Staff
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