Determining Your Risk of Colorectal Cancer

Colorectal cancer is the third most common cancer in the U.S., with more than 140,000 people diagnosed each year. However, it’s also one of the most easily prevented. Many cases of colon or rectal cancer could be avoided by getting screened and making certain lifestyle adjustments.

Estimate your risk for colon cancer.

What are the risk factors for colorectal cancer?

Some of the risk factors for colorectal cancer are connected to basic aspects of our biology, such as our age and height. But other risk factors are caused by our lifestyles, such as the amount of red meat we eat and alcohol we drink. These are areas to take action.

Advanced age

Our risk for colorectal cancer goes up as we age, especially after 60.

Being tall

Colorectal cancer risk is higher in women who are 5 feet, 8 inches or taller, and in men who are 5 feet, 11 inches and taller.

Inflammatory bowel disease

People with inflammatory bowel disease, such as Crohn’s or ulcerative colitis, have five times the risk of developing colorectal cancer.

Not getting screened

Having regular screening for colorectal cancer is the single best way to protect yourself. You can catch cancer earlier when it’s most treatable or prevent it from happening in the first place.

Being overweight

Always try to keep weight within a healthy range. Being overweight can increase our risk for many cancers, including colorectal cancer.

Diet high in red and processed meat

Limit red meat, such as steak, hamburger and pork; and processed meat, such as bacon, sausage and bologna, to less than three servings a week.

Low physical activity

Do something active you enjoy for at least 30 minutes a day to lower your risk of colon cancer. Activity also helps keep your weight down.

Too much alcohol

If you drink, keep it to one drink or less a day. Even moderate amounts increase the risk of colon cancer.


On top of raising our risk of heart disease, stroke and emphysema, smoking is a major cause of at least 14 different cancers, including colon cancer. If you smoke, quit.

Low calcium and vitamin D

There is good evidence that adequate calcium and vitamin D protect against colon cancer. Shoot for about 1,200 mg a day of calcium and 1,000 IU a day of vitamin D.

Lack of folate

A daily multivitamin with folate is good for nutrition and can also protect against colon cancer. One a day is all you need.

Genetic risk factors for colorectal cancer

Up to 5-6 percent of colorectal cancers are caused by inherited cancer syndromes. If you have a strong family history of colorectal cancer or cancer-related conditions, you may be advised to start an alternative screening schedule. Generally, this means that you will start getting screened at a younger age and may be screened more frequently.

Having a family history of colorectal cancer means that one or more of your relatives has developed it, especially one of your parents, siblings, or children. Additionally, a relative may have developed colorectal cancer at an early age. If colorectal cancer doesn’t seem to run in your family, but multiple family members have developed a different cancer or one family member has several types of cancer, you should still mention it to your doctor.

Genetic testing for inherited cancer syndromes can help you make treatment and screening decisions under certain conditions. Washington University Physicians and genetic counselors at Siteman help identify and support patients with familial predispositions to cancers like colorectal cancer. Siteman maintains a registry of patients with known inherited tendencies for colon cancer.

Genetic syndromes include:

Familial adenomatous polyposis (FAP)

This hereditary colon cancer syndrome is caused by an abnormal alteration in the APC gene. Individuals develop hundreds to thousands of polyps in their colons. Since any of the polyps may become cancerous, removal of the colon is recommended. Polyps may develop in other areas of the digestive system, requiring lifelong cancer screening.

Most of the patients in Siteman’s registry have FAP.

Hereditary non-polyposis colorectal cancer (HNPCC)

This hereditary colorectal cancer syndrome involves an abnormal change in one of at least four genes. Individuals with HNPCC have an 80 percent lifetime risk of developing colorectal cancer. Women with HNPCC also have a 40-60 percent lifetime risk of developing uterine cancer. Other cancers, such as gastric or kidney tumors, may be associated with this syndrome. Colorectal cancer screening and uterine cancer screening are recommended, beginning at a young age. Other screening may be recommended based on family history.

How can I lower my risk of colorectal cancer?

Anyone can take steps to lower his or her risk of colorectal cancer. These steps include:

  • Getting regular screenings
  • Losing weight
  • Limiting red and processed meat consumption
  • Reducing alcohol intake
  • Exercising
  • Taking a daily multivitamin
  • Quitting smoking

Am I too young to get colorectal cancer?

Many young people assume that they cannot get colorectal cancer unless they are middle-aged or older. This sometimes leads them, and even their physicians, to dismiss troublesome symptoms simply as digestive problems.

It’s true that colorectal cancer is more likely to occur in older or elderly populations. But recent research, including some done right here at Siteman, shows that increasing numbers of young people are developing colorectal cancer.

If you experience any of the symptoms of colorectal cancer, especially blood in the stool, unwanted weight loss, loss of appetite, or unexplained anemia, you should make an appointment with your doctor. Tell him or her that you are concerned about cancer, and don’t hesitate to get a second opinion if you feel that you aren’t being taken seriously. While it’s still unlikely that cancer is causing your symptoms, you might be suffering from another gastrointestinal issue that needs to be addressed.

Risk calculators and resources

Though it’s best to discuss your risk factors with your doctor in person, digital tools and resources can be a helpful place to start.  Keep in mind that any risk calculations you receive are only estimates.

Your Disease Risk

Physicians and researchers at Washington University and Barnes-Jewish Hospital have developed risk assessment tools for many different diseases and forms of cancer. To learn your risk and how to lower it, take the assessment for colorectal cancer.