What causes colon and rectal cancers?

Several factors may place you at a higher risk for colorectal cancer.

If you have any of the following risk factors, speak with your physician about when you should undergo colon cancer screening.

There are risks you cannot control, as well as risks you can control.


Risks You Cannot Control


Over 90% of those diagnosed with colorectal cancer are over age 50. As we age, we are more likely to grow polyps which have the gene changes that turn normal tissue into cancer. All average-risk adults age 45 should talk to their doctors about colorectal cancer screening. Adults who have a high risk of CRC should talk to their doctors about getting screened earlier.

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Personal History of Polyps or Cancer

If you have a personal cancer history of colon polyps or colon cancer, rectal cancer, ovarian cancer, endometrial cancer or breast cancer – you may be at an increased risk of colorectal cancer.

You may want to talk with your doctor about whether genetic testing is appropriate for you.

Inflammatory Bowel Disorders (IBD)

If you’ve been diagnosed with an inflammatory bowel disorder such as ulcerative colitis or Crohn’s Disease, you are at a higher risk for colorectal cancer.

Talk with your doctor about when your screening should begin.

Family History & Genetics

If you or a family member has a history of colorectal cancer, or colon polyps, you may be at an increased risk for colorectal cancer.

Generally, screening for family members is recommended to begin 10 years prior to the survivor’s age of diagnosis.

For example, if your loved one was diagnosed at age 52, family member screening needs to begin at age 42.

If your family has a known genetic syndrome, screening may be recommended earlier.

Talk to your doctor if you have a family history of CRC.

Even if not inherited, other genetic syndromes may increase your chances of colorectal cancer.  Learn more about genetic risk factors in our Genetics Mini Magazine.

Rev. Roland Cooper had a family history of the disease, his sister was also diagnosed.

Here’s his story:

Read more about Rev. Cooper’s story.

Risks You Can Control


Low physical activity, obesity, smoking and heavy alcohol use are all linked to a higher incidence of colorectal cancer.


A diet high in red meats (beef, pork, lamb) processed meats and fats may all be linked to colorectal cancer.

Preventing CRC

While colorectal cancer screening is the most important way to prevent colorectal cancer, there are lifestyle changes that can reduce your risk for polyps and colorectal cancer.

There is convincing evidence that the following strategies can decrease colorectal cancer risk:

    • Don’t smoke
    • If you do smoke, stop
    • Increase your physical activity (get at least 150 minutes of moderate intensity or 75 minutes of vigorous intensity activity each week)
    • Maintain a healthy body weight
    • Avoid overall body fat, especially fat around your waist
    • Reduce how much red meat and processed meats you eat
    • Use alcohol in moderation

There is probable evidence that these additional strategies can reduce risk:

    • Increase foods that contain dietary fiber
    • Include garlic in your diet
    • Drink more milk if you can tolerate it
    • Add foods with calcium
    • Use alcohol in moderation

Want to know more? Read our blog about the Foods that Make Headlines

Colorectal Cancer Under 50 Years Old

2016 OMS CollectionWhile over 90% of colon and rectal cancers are found in people over the age of 50, anyone at any age can get colorectal cancer.

People younger than age 50 need to protect themselves by knowing their family cancer history and their own medical history.

Those with a family history of certain cancers, or with certain medical conditions, may need to begin screening earlier and be tested more often.

These situations could elevate someone’s risk.

In addition, everyone, no matter how old they are, should be aware of the signs and symptoms of colorectal cancer. If you’re experiencing any of these symptoms, talk to your doctor about the appropriate screening for you.

Learn more about how Fight CRC is driving research for those Under 50.