What Is Colorectal Cancer and How Can You Lower Your Risk?

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What Is Colorectal Cancer and How Can You Lower Your Risk?

Receiving a diagnosis of colorectal cancer can be devastating — for you and for your loved ones. Luckily, for many types of cancer, there are better treatments available than ever before, and people who have cancer are living longer lives. However, the goal is to avoid having cancer in the first place. And there are steps that you can take to lower your risk of getting colorectal cancer.

What is colorectal cancer?

According to the CDC (Centers for Disease Control and Prevention), “Not counting some kinds of skin cancer, colorectal cancer is the third most common cancer in men and women. It is the third leading cause of cancer-related deaths in the United States.”


The colon (also called the large intestine or large bowel) is the part of the digestive tract that absorbs water and electrolytes, and forms and stores stool (feces). The rectum is at the end of the colon, right above the anus; this part of the intestine holds stool before it passes out of the body through the anus.

Colorectal cancer (often called “colon cancer”) is cancer that occurs in the colon. Most of the time, colorectal cancer starts as a growth on the inner lining of the colon or rectum, says the American Cancer Society. These growths are called polyps, and there are different types.

Not all polyps become cancerous, but some do. For example, adenomatous polyps, sessile serrated polyps, and traditional serrated adenomas are more likely to become cancerous. The risk of colorectal cancer is also higher if:

  • A polyp is larger than one centimeter
  • More than three polyps are found
  • Dysplasia (a precancerous condition) is found in the polyp or in the lining of the colon or rectum

What are symptoms of colorectal cancer?

Colorectal polyps and colorectal cancer don’t always cause symptoms, at least right away. You may have a polyp or colorectal cancer and not know it, which is why regular screening is so important.

Typical symptoms of colorectal cancer may include:

  • A change in your bowel habits — e.g., constipation, diarrhea, narrowing of the stool — that lasts for more than a few days
  • Feeling that you need to have a bowel movement that doesn’t go away after having one
  • Blood in or on your stool
  • Cramping or belly pain
  • Unexplained weight loss
  • Weakness or fatigue

All of these symptoms can happen due to other factors, too, such as having an infection, irritable bowel syndrome, or inflammatory bowel disease. That’s why it’s so important to get screened and let your health care provider know if you have these symptoms.

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What are the risk factors for colorectal cancer?

There are several risk factors that can increase your chances of developing colorectal cancer. Of these, some you are unable to change. These include having:

  • Inflammatory bowel disease, such as ulcerative colitis or Crohn’s disease
  • A family history of colorectal cancer or adenomatous polyps
  • A genetic condition, such as familial adenomatous polyposis or Lynch syndrome
  • Diabetes

Being older raises your risk of colorectal cancer. It’s much more common in people over the age of 50, although the rate is increasing in younger adults.

Fortunately, there are risk factors that you CAN change, such as:

How is having diabetes linked to a higher risk of colorectal cancer?

People with type 2 diabetes have a higher risk of getting colorectal cancer. A study published in 2017 states that the risk of colorectal cancer was estimated to be 27% higher in people with type 2 diabetes than in people without diabetes, although other research suggests that the risk could be higher. While reasons for this aren’t entirely clear, one thought is that high levels of insulin and glucose may promote the growth of cancer cells. Another possibility is that constant hyperglycemia (high blood sugar levels) and chronic inflammation due to diabetes are culprits.

How is colorectal cancer diagnosed and treated?

If your symptoms indicate that you could have colorectal cancer, you will likely have one or more of the following tests:

  • Colonoscopy to view your entire colon using a thin tube with a light on the end
  • Biopsy of the tissue where the cancer could be.
  • CT scan
  • Ultrasound
  • Gene and protein tests of the biopsy tissue
  • Blood tests

If colorectal cancer is diagnosed, the cancer may be “staged” to help determine the right course of treatment. Depending on the extent of the cancer, treatment may include the removal of the cancerous polyps, removal of part of the colon, chemotherapy, radiation therapy, targeted drug therapy, and/or immunotherapy.

Seven ways to lower your colorectal cancer risk

You’re in the driver’s seat when it comes to lowering your risk of colorectal cancer. Here’s how:

1. Get screened.

The American Cancer Society recommends screening starting at the age of 45 for those at average risk. Screening can include stool tests, flexible sigmoidoscopy, colonoscopy, or CT colonography. Screening helps find precancerous polyps early, before they turn into cancer. Talk with your provider about what’s best for you and how often you should be screened.

2. Fix up your diet.

This means focusing on getting a lot of vegetables, fruits, and whole grains in your eating pattern. These foods are linked with a lower risk of colorectal cancer. At the same time, try to cut back on eating too much red meat (e.g., beef, pork, lamb, veal) and processed meats, as these foods can increase your risk. A dietitian can help you make changes to your eating plan.

3. Be more active.

Not only will this help you better manage your blood sugars and your weight, but it can also lower your colorectal cancer risk, too.

4. Focus on your weight.

Losing weight and keeping it off can be hard. But a small amount of weight loss helps lower your risk of colorectal cancer and can help improve your health in so many other ways. Talk with your provider or dietitian about weight-loss approaches that are right for you.

5. Don’t smoke.

Smoking increases the risk of developing and dying from colorectal cancer (plus other types of cancer and disease, too).

6. Go easy with alcohol.

Even drinking a small amount of alcohol can increase your risk. If you do drink alcohol, aim for no more than two servings a day for men and no more than one daily for women. A serving is 12 ounces of beer, 5 ounces of wine, or 1.5 ounces of 80-proof distilled spirits (hard liquor).

7. Help your diabetes.

Since having type 2 diabetes boosts your colorectal cancer risk, working on keeping your blood sugars in your target range will help you lower your risk. Many of the steps listed above can make it easier for you to manage your diabetes. In addition, taking your diabetes medications as prescribed and checking your blood sugars regularly help, too!

Also, there’s some research that points to the use of low-dose aspirin to help prevent colorectal cancer, as well as heart disease. Talk with your provider about the risks and benefits of taking aspirin.

For more lifestyle tips and information on lowering your risk of cancer, visit the American Cancer Society’s webpage here

Want to learn more about maintaining a healthy gut? Read “Five Ways to Improve Gut Health” and “Diabetes and the Microbiome.”

Amy Campbell, MS, RD, LDN, CDCES

Amy Campbell, MS, RD, LDN, CDCES

Amy Campbell, MS, RD, LDN, CDCES on social media

A Registered Dietitian and Certified Diabetes Educator at Good Measures, LLC, where she is a CDE manager for a virtual diabetes program. Campbell is the author of Staying Healthy with Diabetes: Nutrition & Meal Planning, a co-author of 16 Myths of a Diabetic Diet, and has written for  publications including Diabetes Self-Management, Diabetes Spectrum, Clinical Diabetes, the Diabetes Research & Wellness Foundation’s newsletter,, and

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