Cancers of the lung, breast in women, and prostate in men are the only cancers more common than colorectal cancer.

But colorectal cancer can also happen at younger ages, and the risk goes up as you get older. The ACS recommends regular screenings for colorectal cancer for people at average risk starting at age 45. Some people at high risk should start even earlier. Some screening tests can find and remove small precancer growths called polyps before they have a chance to become cancer.

At first, colorectal cancer often has few or no symptoms. That’s why it’s so important to get regular screenings. Symptoms can include blood in or on the stool; a change in bowel habits; stools that are narrower than usual; general stomach discomfort; decreased appetite; and unexplained weight loss. See your healthcare provider if you notice any of these symptoms.

Most colorectal cancers start as polyps. These are tiny growths on the inner lining of the colon or rectum that may become cancer over time.

Family history does raise your risk, but most people with colorectal cancer don't have a strong family history of it. Other risk factors are increased age (it's more common in those 50 and older); a personal history of colorectal polyps or cancer; being African American; certain diseases of the bowels; and type 2 diabetes. Other risk factors you can change. For instance, your risk is higher if you are overweight or obese. It's also higher if you eat a lot of red and processed meats; are not physically active; drink a lot of alcohol; or smoke.

Many tests are used for colorectal cancer screening. They include:

• Fecal occult blood test (FOBT) and fecal immunochemical test (FIT). These check for blood in the stool.
• Stool DNA test. This checks the stool for pieces of DNA from polyps or cancer. It also checks for blood in the stool.
• Colonoscopy. This is a test that looks at the inside of the entire colon and rectum through a flexible, lighted tube called a colonoscope. The doctor can take out small pieces of tissue, cells, or polyps for testing through the colonoscope.
• Sigmoidoscopy. For this test, a thin lighted tube is used to look at the inside of the rectum and lower part of the colon. The doctor can use the tube to take out small pieces of tissue, cells, or polyps for testing.
• Virtual colonoscopy. This is a detailed CT scan of the colon and rectum.

You get ready for each test in a different way, and each has a different schedule. Talk with your doctor about which test might be right for you. No matter which test you choose, the most important thing is to get screened.

Researchers have found that people who lead a sedentary lifestyle have a higher risk for colorectal cancer. Making moderate or vigorous physical exercise part of your life may help lower your risk. It can also help you get to and stay at a healthy weight. This also lowers your risk.

A diet high in vegetables, fruits, and whole grains appears to lower the risk for colorectal cancer. Studies have also found a link between red meat (beef, pork, and lamb) and processed meats (hot dogs, sausage, and deli meats) and colorectal cancer. So eating less of these meats can also help lower your risk for colorectal cancer.