What are the risk factors for colorectal cancer?

Colorectal cancer is a type of cancer that develops in the colon or the rectum. It is the fourth most common cancer diagnosed in the U.S.

Here, I’ll discuss what makes you more likely to develop colorectal cancer and what you can do to lower your risk.

What are colorectal cancer risk factors?

Several things can increase your chances of getting colorectal cancer. These risk factors include:

Age

Most people diagnosed with colorectal cancer are older than 50. However, in recent years, we have seen a rise in colorectal cancer cases in young adults.

Family history

If you have a first-degree relative (e.g., parent, sibling or child) with a history of colorectal cancer or colorectal polyps, you are more likely to develop colorectal cancer.

Hereditary cancer syndrome

Some people inherit genetic changes that increase their risk for colorectal cancer. The most common hereditary cancer syndromes linked to colorectal cancer are Lynch syndrome and familial adenomatous polyposis (FAP).

Up to about 20% of colorectal cancer patients under age 50 may have a hereditary cancer syndrome. We recommend genetic counseling and genetic testing for these patients.

Obesity

Individuals with a body mass index (BMI) that is above average have a higher chance of developing many diseases, including colorectal cancer. A healthy BMI is 19-24. 

Tobacco use

If you use tobacco, including smoking cigarettes and chewing tobacco, you’re more likely to develop colorectal cancer.

Diet

Eating a lot of red meat, processed meat and grilled/charred meat can increase your risk for colorectal cancer.

Inflammatory bowel disease

You have a much greater risk for colorectal cancer if you have a history of inflammatory bowel disease, like Crohn’s disease or ulcerative colitis.

Race

Black men and women have the highest rate of colorectal cancer among all racial groups in the U.S.

Personal history of colorectal cancer or colorectal polyps

If you’ve had colorectal cancer or colorectal polyps before, you’re more likely to develop colorectal cancer. The number of polyps and type of polyps can help determine what your future colorectal cancer risk may look like.

Heavy alcohol use

If you drink a lot of alcohol, that can raise your risk for colorectal cancer. While no alcohol is best, women who choose to drink should have no more than one drink a day, and men no more than two drinks a day.

Lack of physical activity

A sedentary lifestyle increases the risk of colorectal cancer. Staying active throughout the day and getting regular exercise can help lower your risk for colorectal cancer and other diseases. Aim for at least 150 minutes of moderate exercise, like brisk walking, or 75 minutes of vigorous exercise, like running, each week.

What is a high-risk feature for colon cancer?

We often use the phrase “high-risk feature” when talking about the prognosis for stage II and stage III disease. High-risk features are things pathologists look for on colon cancer tumors that help us identify if there is a high risk for relapse, or the cancer coming back. The size of the tumor is one example of a high-risk feature.

For example, a person with stage II colon cancer may have tumors with high-risk features that make the cancer more likely to relapse compared to another person with stage II disease with tumors that do not have these features.

How can you lower your colorectal cancer risk?

There are several things you can do to help decrease your risk of getting colorectal cancer. These include:

Get regular colorectal cancer screenings

Colorectal cancer is preventable and easier to treat when it’s found early. Colonoscopy is considered the gold standard for colorectal cancer screening, but other tests are available.

It’s important to get your first colonoscopy at age 45 if you’re at average risk for colorectal cancer, and then every 10 years after that, if no polyps are found.

During a colonoscopy, doctors can remove precancerous polyps so that they don’t turn into cancer later on. Additionally, screening tests can find colorectal cancer early, when it’s easier to treat.

Check with your doctor to determine when and how often you should get screened. People at higher risk for colorectal cancer often need to start screening earlier and be screened more frequently.

Make healthy lifestyle choices

A healthy diet and regular exercise can help lower your chances of developing colorectal cancer.

Eat meals rich in whole grains, vegetables, fruits, beans, nuts and seeds. Limit red meat, processed meat and meat cooked at high temperatures.

Regular physical activity can help you maintain a healthy weight, which can reduce your risk for colorectal cancer.

For cancer prevention, it’s best not to drink alcohol.  If you stop drinking, the risk of alcohol-related cancer declines over time. 

If you use tobacco, stop. There are resources to help you quit, including MD Anderson research studies.

While there are certain factors that can increase your risk for colorectal cancer, remember: there are steps you can take to lower your risk and find the disease early.

Jason Willis, M.D., Ph.D., is a gastrointestinal medical oncologist at MD Anderson.

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