By Dr. Graham A. Colditz

Siteman Cancer Center

We’ve seen great progress in the fight against colorectal cancer. While it’s still one of the most common cancers in the U.S., annual rates of new cases have dropped by nearly half since the mid-1980s.

More recently, though, there’s been a concerning increase in colorectal cancers in adults under age 50, with the rates appearing even higher among African American persons and residents of the South. And it’s unclear why.

“That’s the million-dollar question,” said Dr. Will Chapman Jr., an assistant professor at Washington University School of Medicine in St. Louis who specializes in colon and rectal surgery.

“Though many people are working on the issue, we have not yet developed a clear understanding of what is driving cancer development in younger adults,” he said. “There are certainly some suspects – for example, diets higher in processed foods and/or low in fiber, hormone changes related to obesity and diabetes or changes in the healthy bacteria living in the gut.”

While the exact causes of younger adult colorectal cancer are still being studied, we do know some key steps can help protect against the disease.

No. 1 is to get recommended screening tests. Screening can find cancer earlier when it’s more treatable. It can also help prevent colorectal cancer in the first place, by finding and removing growths that could become cancer.

Most people should get screened starting at age 45, and those at increased risk may need to start earlier and be screened more often. Colonoscopy is the most common screening test and is typically done once every 10 years. But other recommended tests are also effective, including the fecal immunochemical test (FIT) or the stool DNA test. These types of tests are quicker and easier than colonoscopy, but they also need to be done more often. And if they happen to find anything suspicious, they’re usually followed up with a colonoscopy.

Knowing your family history of colorectal or other cancers, particularly if family members had cancer at younger ages, can help doctors estimate your risk of the disease, and if you might benefit from screening at a younger age than most people.

Being aware of symptoms of colorectal cancer is also key – as is immediately reporting anything unusual to a doctor so it can be checked out and followed up if needed, Chapman said. As with screening, reporting symptoms early can help find a cancer earlier when it may be more treatable. Symptoms of colorectal cancer include intermittent red blood with bowel movements or a change in bowel habits, typically in the form of smaller-diameter stools.

“However, many colon and rectal cancers do not have symptoms – which is why screening is so important,” Chapman said.

We also know that healthy behaviors can help prevent colorectal cancer – and that many of the same healthy behaviors that lower the risk of the disease in general likely also help lower the risk in younger adults. Screening tops the list. But other healthy steps include keeping weight in check, not smoking, not drinking alcohol, being physically active and eating a healthy diet rich in whole grains and fiber and limited in red and processed meats.

Ongoing research is telling us more about what causes colorectal cancer in young adults. We’re also learning more about the effects that family history, genetics, race and ethnicity may have on young adult colorectal cancer risk, treatment and follow-up care. As this knowledge develops, we can still take important steps right now to help protect ourselves – and our families – from the disease.

It’s your health. Take control.

For more on ways to lower the risk of colon and other cancers, visit 8ways.wustl.edu.

Dr. Graham A. Colditz, associate director of prevention and control at Siteman Cancer Center at Barnes-Jewish Hospital and Washington University School of Medicine in St. Louis, is an internationally recognized leader in cancer prevention and the creator of the free prevention tool YourDiseaseRisk.com.