Colorectal Cancer Screening and Risk Reduction
Colorectal cancer starts in the colon or the rectum. These cancers can also be called colon cancer or rectal cancer, depending on where they start. Colon cancer and rectal cancer are often grouped together because they have many features in common.
The most important thing is to get screened, no matter which test you choose. Each test has different risks and benefits, and some tests might be better options for you than others. These tests can be divided into 2 main groups:
- Stool-based tests: These tests check the stool (feces) for signs of cancer. These tests are less invasive and easier to do, but they need to be done more often.
- Visual (structural) exams: These tests look at the structure of the colon and rectum for any abnormal areas. This is done either with a scope (a tube-like instrument with a light and tiny video camera on the end) put into the rectum, or with special imaging (x-ray) tests.
It is recommended that people at average risk of colorectal cancer start regular screening at age 45. This can be done either with a sensitive test that looks for signs of cancer in a person’s stool (a stool-based test), or with an exam that looks at the colon and rectum (a visual exam). These options are listed below.
People who are in good health and with a life expectancy of more than 10 years should continue regular colorectal cancer screening through the age of 75.
For people ages 76 through 85, the decision to be screened should be based on a person’s preferences, life expectancy, overall health, and prior screening history.
People over 85 should no longer get colorectal cancer screening.
How to get screened for colorectal cancer
To request a screening for colorectal cancer, speak with your doctor about whether or not you are eligible. If you meet the high-risk criteria, your doctor will have a shared-decision making discussion with you to help decide if you want to do a colorectal cancer screening.
| Test and type | Benefits and limits |
|---|---|
| Fecal immunochemical test (FIT) - Stool based test |
Benefits: No direct risk to the colon. No bowel preparation. No pre-test diet or medication changes needed. Sampling done at home. Fairly inexpensive. Limits: Can miss many polyps and some cancers. Can have false-positive test results. Needs to be done every year. Colonoscopy will be needed if abnormal. |
| Guaiac-based fecal occult blood test (gFOBT) - Stool based test |
Benefits: No direct risk to the colon. No bowel preparation. Sampling done at home. Inexpensive. Limits: Can miss many polyps and some cancers. Can have false-positive test results. Pre-test diet changes (and possibly medication changes) are needed. Needs to be done every year. Colonoscopy will be needed if abnormal. |
| Stool DNA test - Stool based test |
Benefits: No direct risk to the colon. No bowel preparation. No pre-test diet or medication changes needed. Sampling done at home. Limits: Can miss many polyps and some cancers. Can have false-positive test results. Should be done every 3 years. Colonoscopy will be needed if an abnormal result is found. Insurance coverage will vary. |
| Colonoscopy - Visual exam |
Benefits: Can usually look at the entire colon. Can biopsy and remove polyps. Done every 10 years. Can help find some other diseases. Limits: Can miss small polyps. Full bowel prep needed. Costs more on a one-time basis than other forms of testing. Sedation is usually needed; in which case you will need someone to drive you home. You may miss a day of work. Small risk of bleeding, bowel tears, or infection. |
| CT colonography (virtual colonoscopy) - Visual exam |
Benefits: Fairly quick and safe. Can usually see the entire colon. Done every 5 years. No sedation needed. Limits: Can miss small polyps. Full bowel prep needed |
| Flexible sigmoidoscopy - Visual exam |
Benefits: Fairly quick and safe. Usually doesn’t require full bowel preparation. Sedation is usually not used. Does not require a specialist. Done every 5 years. Limits: Not widely used as a screening test. Looks at only about a third of the colon. Can miss small polyps. Cannot remove all polyps. May be some discomfort. Small risk of bleeding, infection, or bowel tear. Colonoscopy will be needed if abnormal. |
- Get screened: If you are 45 or older, you should start getting screened for colorectal cancer. Several types of tests can be used. Talk to your doctor about which ones might be good options for you.
- Weight: Being overweight or obese increases the risk of colorectal cancer in both men and women, but the link seems to be stronger in men. Staying at a healthy weight may help lower your risk
- Physical activity: Being more active lowers your risk of colorectal cancer and polyps. Regular moderate to vigorous activity can lower the risk. Limiting your sitting and lying down time may also lower your risk. Increasing the amount and intensity of your physical activity may help reduce your risk.
- Diet: Overall, diets that are high in vegetables, fruits, and whole grains, and low in red and processed meats, probably lower colorectal cancer risk, although it’s not exactly clear which factors are important. Many studies have found a link between red meats (beef, pork, and lamb) or processed meats (such as hot dogs, sausage, and lunch meats) and increased colorectal cancer risk.
- Alcohol: Several studies have found a higher risk of colorectal cancer with increased alcohol intake, especially among men. It is best not to drink alcohol. For people who do drink, they should have no more than 1 drink per day for women or two drinks per day for men. Not drinking alcohol may help reduce your risk.
- Smoking: Long-term smoking is linked to an increased risk of colorectal cancer, as well as many other cancers and health problems. Quitting smoking may help lower your risk of colorectal cancer and many other types of cancer, too.
- Vitamins: Long-term smoking is linked to an increased risk of colorectal cancer, as well as many other cancers and health problems. Quitting smoking may help lower your risk of colorectal cancer and many other types of cancer, too.
- NSAIDs: Many studies have found that people who regularly take aspirin or other non-steroidal anti-inflammatory drugs (NSAIDs), such as ibuprofen (Motrin, Advil) and naproxen (Aleve), have a lower risk of colorectal cancer and polyps.
- Hormone replacement therapy for women: Some studies have shown that taking estrogen and progesterone after menopause (sometimes called menopausal hormone therapy or combined hormone replacement therapy) may reduce a woman’s risk of developing colorectal cancer, but other studies have not.
Know the facts, risk factors, and cancer screening options. View and download educational material below.