Don’t have a doctor?
Screening is available for all Canadians. Find out where you can get checked.
Colon cancer grows very slowly. There usually aren’t any noticeable symptoms in the early stages. But there are tests to check the colon for early signs of cancer, before symptoms appear or even before the cancer starts to grow. Getting checked regularly for colon cancer is called screening.
Take the first step. Talk to your doctor.
Ask your doctor about colon cancer screening. Your doctor can tell you what tests are available and which screening test is best for you.
Screening tests for colon cancer
Types of stool tests
There are 2 types of stool tests for colon cancer screening.
gFOBT (or simply FOBT) uses the chemical guaiac to find blood in the stool.
FIT uses antibodies to find blood in the stool.
Find out how to do the stool test at home.
Stool tests are used to look for hidden traces of blood in the feces or bowel movement, because colon cancer lesions and polyps (pre-cancerous growths) can sometimes bleed. The two types of stool tests used for colon cancer screening in Canada are FOBT and FIT. FOBT stands for fecal occult blood test. FIT stands for fecal immunochemical test.
Find out how to do the test. It’s simple.
If no blood was found (normal test result)
If blood was not found in the stool, then the test result is considered “normal.” (This is also called a “negative test result”.) With this test result, you will be asked to do the test again every year or every two years.
If blood is found (abnormal test result)
An abnormal result will require more tests. Since finding blood in stool does not always mean cancer, more testing will rule out other conditions, such as ulcers or hemorrhoids (which also show blood in stool). To find out why you have blood in your stool, you may have a colonoscopy.
For a colonoscopy, the doctor uses a long, flexible tube that has a camera and a light attached at the end. It is inserted in the colon to look for polyps or anything else that looks abnormal. You will likely have a colonoscopy if:
- the stool test results were abnormal (blood was found). A colonoscopy will help the doctors find out what is going on.
- you are at high risk for getting colon cancer. Your first screening test may be a colonoscopy. (Talk to your doctor if someone in your family has had colon or rectal cancer.)
Find out how to prepare for a colonoscopy and what you can expect.
The stool test (FOBT or FIT) and colonoscopy are the most common screening tests for colon cancer in Canada. You may hear of other tests, such as:
Double-contrast barium enema
A double-contrast barium enema is a special x-ray of the colon. For this test, your colon has to be completely empty. Your doctor will give you special instructions to follow before the test.
The test takes about 30 minutes. You will not need sedation. A mixture of air and barium (a liquid that shows up on the X-ray) will be put into your colon through a tube placed in the rectum. The doctor watches the barium pass through the colon and looks for polyps or other abnormalities. The test can be uncomfortable and you may wish to have someone to take you home afterwards.
Similar to a colonoscopy, the doctor uses a thin, flexible tube with a camera and a light at the end to look inside the rectum and the lower part of the colon. (A colonoscopy looks at the rectum and the entire colon.) For this test, your colon has to be empty. Your doctor will give you special instructions to follow before the test.
The test takes about 10 to 20 minutes. Most people do not need sedation for a sigmoidoscopy.
The virtual colonoscopy is a newer, less invasive test that takes pictures of the colon using a CT scanner (a machine that takes X-rays from multiple angles as it rotates around your body). The scanner compiles the pictures to make a 3-D image. Using a virtual colonoscopy, the doctor can see inside the colon and look for polyps or anything else that looks abnormal.
Like with a regular colonoscopy, your colon must be completely empty for this test. Your doctor will give you special instructions (for diet and medications) to follow before the test. If the doctor finds polyps or other abnormalities, you will need to have a colonoscopy so that the doctor can take a biopsy.