Colorectal cancer (also known as colon cancer) is cancer of the colon and/or rectum and happens when a growth in the lining of the colon or rectum becomes cancerous.

Most colorectal cancers come from precancerous polyps — adenomatous polyps or serrated polyps — that form over many years (5 to 10) to become a cancer. A polyp is a mushroom-like or flat growth on the inside wall of the colon or rectum. Polyps grow slowly over many years. Not all colon polyps have the same risk of turning into colon cancer. Precancerous polyps could become cancerous; other types of polyps (hyperplastic, inflammatory) do not.

If you are at average risk, colorectal cancer screening should start at age 45.

If you have a family history of colorectal cancer or polyps, start screening at age 40 or the age that is 10 years younger than the earliest member of your family was diagnosed with colorectal cancer or polyps, whichever is earlier.

If you have inflammatory bowel disease (IBD, Crohn’s disease or ulcerative colitis), or a history of abdominal radiation, talk to your health care provider about when you should start screening for colorectal cancer.

If you think you might be at high risk for colorectal cancer, talk to your health care provider early, before age 45, to make a screening plan that’s right for you.

Colorectal cancer does not cause symptoms early, which is why routine screening is essential. With routine colorectal cancer screening, more than 1 out of every 3 colorectal cancer deaths can be avoided.

Colorectal cancers found in people without symptoms are not as advanced and are more frequently cured. Colorectal cancer screening can detect cancers at an early stage, which can increase your chance of cure and survival. Also, there are more treatment options when colorectal cancer is diagnosed at an early state.

Colorectal cancer screening is safe, effective, and recommended for all adults starting at age 45. There are several tests for colorectal cancer screening, such as colonoscopy, but there are also tests that are noninvasive, meaning they don’t need tools that enter your body. Talk with your primary care provider or gastroenterologist to discuss your CRC screening options and insurance coverage.

• Colonoscopy: A colonoscopy involves looking at the colon from inside the body using a long, thin (about the width of your little finger), flexible tube with a tiny camera on the end, through which the doctor can view your whole colon and rectum for polyps or cancer. Colonoscopy is the only CRC screening test that blends both prevention (by getting rid of polyps that could lead to cancer) and early detection of cancer. How often you need a colonoscopy depends on personal risk and prior colonoscopy findings. If you don’t have a family history of CRC or prior personal polyps, you will need to have a colonoscopy every 10 years. Your gastroenterologist will tell you when to have your next colonoscopy.
• Fecal immunochemical test (FIT): A noninvasive stool test that you do at home. FIT works by finding hidden, invisible blood in your stool. It’s low cost and pretty easy to do. FIT can be used by individuals who are at average risk of colorectal cancer. If the results are positive (or abnormal), you will need to have a colonoscopy. A FIT test must be done every year.
• Fecal occult blood test (FOBT): A noninvasive stool test that you do at home, but you will need to follow a special diet before doing the test. FOBT works by finding hidden, invisible blood in your stool. It’s low cost and pretty easy to do. FOBT can be used by individuals who are at average risk of colorectal cancer. If the results are positive (or abnormal), you will need to have a colonoscopy. An FOBT test must be done every year.
• Stool-DNA: A noninvasive stool test that you do at home. A stool-DNA test finds abnormal cell parts, DNA, from colon cancers and polyps and tests for blood in your stool. It’s pretty easy to do, but your health care provider will need to give you a prescription. A stool-DNA test can be used by individuals who are at average risk of colorectal cancer. If the results are positive (or abnormal), you will need to have a colonoscopy. A stool-DNA test must be done every three years.
• Blood-based screening test: The U.S. Food and Drug Administration (FDA) has approved the first blood test as a screening option for colorectal cancer. If the results of the blood test are positive (or abnormal), it suggests that you may have colorectal cancer, and you need to have a colonoscopy to prove the diagnosis. The blood test will not tell you if you have precancerous polyps that could turn into cancer if they are not removed. The blood test must be performed at least every three years.

Learn more about these and other colorectal cancer screening test options.

Keep these questions in mind as you work with your primary care provider or gastroenterologist to figure out which test is best for you.

• What are my risk factors for CRC?
• What are my CRC testing choices given my past medical history?
• What are the risks and benefits of each test option?
• What happens if a polyp is found?
• How do I get ready for my test?
• What can I eat/drink before my test?
• How often should I be tested if my colon is clear?
• If a polyp is found, when should I get tested again?
• How often do you perform each test option?
• How often do you need to do a standard colonoscopy after doing a different test first?

Colorectal cancer does not cause symptoms early, which is why routine screening is essential. As colorectal cancer progresses, there are a number of symptoms or warning signs that can happen, such as:

• Rectal bleeding.
• Blood in your stool (bright red, black or very dark).
• Temporary change in your bowel movements, especially in the shape of the stool (e.g., thin like a pencil).
• Pain in having a bowel movement or the urge to move your bowels without having a bowel movement.
• Frequent cramping pain in your lower belly.
• Frequent gas pains.
• Weight loss without dieting.

Along with getting tested regularly, healthy life choices are usually recommended as the best way to lower your risk of colorectal cancer.

• Do not smoke or use tobacco products.
• Eat more foods that are high in fiber, such as whole grains, fruits and veggies.
• Eat more cruciferous veggies, such as cabbage, broccoli, cauliflower and brussels sprouts.
• Raise calcium intake with low-fat milk, shellfish, salmon and calcium supplements with vitamin D.
• Eat less fats, oils, butter and red meat.
• Limit your intake of charcoal-broiled foods and skip salt-cured foods.
• Limit your intake of highly processed foods.
• Get active.
• Keep your weight in the normal range.
• Limit alcohol intake.