What is Colorectal Cancer?

Colorectal cancer is cancer that occurs in the colon or rectum. Sometimes it is called colon cancer. The colon is the large intestine or large bowel. The rectum is the passageway that connects the colon to the anus.

Screening Saves Lives

If you’re 50 or older, getting a colorectal cancer screening test could save your life. Here’s how:

  • Colorectal cancer usually starts from polyps in the colon or rectum. A polyp is a growth that shouldn’t be there.
  • Over time, some polyps can turn to cancer.
  • Screening tests also can find colorectal cancer early. When it is found early, the chance of being cured is good.

Who Gets Colorectal Cancer?

  • Both men and women can get it.
  • It is most often found in people 50 or older.
  • The risk increases with age.

Are You at High Risk?

Your risk for colorectal cancer may be higher than average it:

  • You or a close relative have had colorectal polyps or colorectal cancer.
  • You have inflammatory bowel disease.
  • You have a genetic syndrome such as familial adenomatous polyposis (FAP) or hereditary nonpolyposis colorectal cancer.

People at high risk for colorectal cancer may need earlier or more frequent tests than other people. Talk to your doctor about when to begin screening and how often you should be tested.

CDC Screen for Life

It’s the Second Leading Cancer Killer

Colorectal cancer is the second leading cancer killer in the United States, but it doesn’t have to be. If everyone aged 50 years or older had regular screening tests, at least 60% of deaths from this cancer could be avoided. So if you are 50 or older, start getting screened now.

Colorectal Cancer Can Start With No Symptoms

Precancerous polyps and early-stage colorectal cancer don’t always cause symptoms, especially at first. This means that someone could have polyps or colorectal cancer and not know it. That is why having a screening test is so important.

What Are the Symptoms?

Some people with colorectal polyps or colorectal cancer do have symptoms. They may include:

  • Blood in or on your stool (bowel movement).
  • Stomach pain, aches, or cramps that don’t go away.
  • Losing weight and you don’t know why.

If you have any of these symptoms, talk to your doctor. These symptoms may be caused by something other than cancer. However, the only way to know what is causing them is to see your doctor.

Types of Screening Tests

Several different screening tests can be used to find polyps or colorectal cancer. Each can be used alone. Sometimes they are used in combination with each other. The U.S. Preventative Services Task Force (USPSTF) recommends colorectal cancer screening for men and women aged 50 – 75 using high-sensitivity fecal occult blood testing (FOBT), sigmoidoscopy, or colonoscopy. Talk to your doctor about which test or tests are right for you. The decision to be screened after age 75 should be made on an individual basis. If you are older than 75, ask your doctor if you should be screened.

High-Sensitivity FOBT (Stool Test)

There are two types of FOBT: One uses the chemical guaiac to detect blood. The other – a fecal immunochemical test (FIT) – uses antibodies to detect blood in the stool. You receive a test kit from your health care provider. At home, you use a stick or brush to obtain a small amount of stool. You return the test to the doctor or a lab, where stool samples are checked for blood.
How often: Once a year.

Flexible Sigmoidoscopy

For this test, the doctor puts a short, thin, flexible, lighted tube into your rectum. The doctor checks for polyps or cancer inside the rectum and lower third of the colon.
How often: Every five years. When done in combination with a High-Sensitivity FOBT, the FOBT should be done every three years.


This is similar to flexible sigmoidoscopy, except the doctor uses a long, thin, flexible, lighted tube to check for polyps or cancer inside the rectum and entire colon. During the test, the doctor can find and remove most polyps and some cancers.
How Often: Every 10 years.

Colonoscopy also is used as a follow-up test if anything unusual is found during one of the other screening tests.

Other Screening Tests in Use or Being Studied

Although these tests are not recommended by the USPSTF, they are used in some settings and other groups may recommend them. Many insurance plans don’t cover these tests, and if anything unusual is found during the test, you likely will need a follow-up colonoscopy.

Double Contrast Barium Enema

You receive an enema with a liquid called barium, followed by an air enema. The barium and air create an outline around your colon, allowing the doctor to see the outline of your colon on an X-ray.

Virtual Colonoscopy

Uses X-rays and computers to produce images of the entire colon. The images are displayed on the computer screen.

Steel DNA Test

You collect an entire bowel movement and send it to a lab to be checked for cancer cells.

Will Insurance or Medicare Pay?

Many insurance plans and Medicare help pay for colorectal cancer screening tests. Check with your plan to find out which tests are covered for you. To find out about Medicare coverage, call 1-800-MEDICARE (1-800-633-4227), or visit

The Bottom Line

If you’re 50 or older, talk with your doctor about getting screened. For more information, visit or call 1-800-CDC-INFO (1-800-232-4636). For TTY, call 1-888-232-6348.