Doctors use a number of tests to screen for colon and rectal cancer. These can be used alone or in combination. We've summed up what happens in these tests. You can use this information to talk to your doctor about which test is best for you.

This is the simplest test. It is often part of a routine physical examination. The doctor puts on latex gloves and then places a finger into your rectum, the part of your bowel nearest to your anus, to feel if any of it is unusual.

The test is usually quick and painless, although some people find it embarrassing. It can only find problems in the lower part of your rectum.

 

 

 

 

 

Source:
National Cancer Institute.
Colorectal cancer screening.
October 2008. Available at http://www.cancer.gov/cancertopics/factsheet/detection (accessed on 10 December 2008).

 

 

 

 

 

¹ This is not recommended as a screening test.

This test looks for blood in your stools. It is called an occult blood test because blood may be hidden in your stools (the word "occult" can mean "hidden"). Bleeding is often an early sign of colon or rectal cancer. This test can pick up tiny traces of blood that may be too small for you to notice.

 

 

 

 

 

Source:
Cancer Research UK.
Bowel cancer tests.
September 2008. Available at http://www.cancerhelp.org.uk/help/default.asp?page=2819 (accessed on 11 December 2008).

 

 

 

 

 

²

You do the test at home, using a special kit. You place a small amount of your stool onto test cards. Then you return the cards to your health care provider so they can be checked for traces of blood.

 

 

 

 

 

Source:
Centers for Disease Control and Prevention.
Colorectal cancer screening.
February 2007. Available at http://www.cdc.gov/cancer/colorectal/basic_info/screening/tests.htm (accessed on 11 December 2008).

 

 

 

 

 

³

There are no health risks with this test. But most polyps and some cancers don't bleed. So, an FOBT will not find all cases of cancer.

 

 

 

 

 

Source:
National Cancer Institute.
Colorectal cancer screening.
October 2008. Available at http://www.cancer.gov/cancertopics/factsheet/detection (accessed on 10 December 2008).

 

 

 

 

 

¹

Sometimes the test comes up with a false positive result. This means that the test finds blood, but you don't have cancer. This is because bleeding can be a sign of many other health problems, such as hemorrhoids.

 

 

 

 

 

Source:
Cancer Research UK.
Bowel cancer tests.
September 2008. Available at http://www.cancerhelp.org.uk/help/default.asp?page=2819 (accessed on 11 December 2008).

 

 

 

 

 

² Most people who get a positive result for an FOBT don't have colon or rectal cancer.

 

 

 

 

 

Source:
NHS Cancer Screening Programmes.
NHS bowel cancer screening programme.
Available at http://www.cancerscreening.nhs.uk/bowel/index.html (accessed on 10 December 2008).

 

 

 

 

 

⁴

For this test, the doctor puts a thin bendy tube (a sigmoidoscope) through your anus and part way into your bowel. A light inside the tube lets the doctor see inside your rectum and the lower part of your colon.

 

 

 

 

 

Source:
Cancer Research UK.
Bowel cancer tests.
September 2008. Available at http://www.cancerhelp.org.uk/help/default.asp?page=2819 (accessed on 11 December 2008).

 

 

 

 

 

²

The test may be carried out at your doctor's office, in a clinic or at a hospital. Before the test you will need to empty your lower bowel completely. You may be given a

 

 

 

 

 

laxative
A laxative is a kind of medicine you can buy over the counter. Laxatives empty your bowels by making you go to the bathroom often.

 

 

 

 

 

laxative to help. Or you may have an

 

 

 

 

 

enema
An enema is liquid that is poured into your rectum to clean it out. Many people find it uncomfortable and embarrassing, but it helps your doctor to see the inside of your bowels.

 

 

 

 

 

enema. If you have an enema, a nurse will run some fluid into your rectum through a tube in your anus. This will clear out your rectum.

 

 

 

 

 

Source:
Cancer Research UK.
Bowel cancer tests.
September 2008. Available at http://www.cancerhelp.org.uk/help/default.asp?page=2819 (accessed on 11 December 2008).

 

 

 

 

 

²

You then lie on a couch on your side while the doctor slides the sigmoidoscope into your anus. Once the tube is in, air is pumped into your bowel, which helps the doctor see the wall of your bowel more clearly.

 

 

 

 

 

Source:
Cancer Research UK.
Bowel cancer tests.
September 2008. Available at http://www.cancerhelp.org.uk/help/default.asp?page=2819 (accessed on 11 December 2008).

 

 

 

 

 

²

During the test, the doctor can remove any polyps and collect samples of any cells that look unusual to examine later.

 

 

 

 

 

Source:
Centers for Disease Control and Prevention.
Colorectal cancer screening.
February 2007. Available at http://www.cdc.gov/cancer/colorectal/basic_info/screening/tests.htm (accessed on 11 December 2008).

 

 

 

 

 

³

This test is usually painless, but it can be a bit uncomfortable. It only lets the doctor see your rectum and the lower part of your colon. The doctor won't be able to see any problems in the upper part of your bowel.

There is a very small chance that the sigmoidoscope might damage the lining of your rectum or colon. This might make it bleed.

 

 

 

 

 

Source:
National Cancer Institute.
Colorectal cancer screening.
October 2008. Available at http://www.cancer.gov/cancertopics/factsheet/detection (accessed on 10 December 2008).

 

 

 

 

 

¹

Some doctors like to use an FOBT and flexible sigmoidoscopy in combination, to increase the chance of finding polyps and cancers. You will probably have an FOBT every year and flexible sigmoidoscopy every five years.

 

 

 

 

 

Source:
Centers for Disease Control and Prevention.
Colorectal cancer screening.
February 2007. Available at http://www.cdc.gov/cancer/colorectal/basic_info/screening/tests.htm (accessed on 11 December 2008).

 

 

 

 

 

³

For this test, the doctor puts a thin bendy tube called a colonoscope into your anus. It's longer than a sigmoidoscope, so it can go further into your bowel. Your doctor can look at the whole of your bowel and rectum.

 

 

 

 

 

Source:
Centers for Disease Control and Prevention.
Colorectal cancer screening.
February 2007. Available at http://www.cdc.gov/cancer/colorectal/basic_info/screening/tests.htm (accessed on 11 December 2008).

 

 

 

 

 

³

Colonoscopy is also used as a follow-up test if your doctor finds any problems during one of the other screening tests.

 

 

 

 

 

Source:
Centers for Disease Control and Prevention.
Colorectal cancer screening.
February 2007. Available at http://www.cdc.gov/cancer/colorectal/basic_info/screening/tests.htm (accessed on 11 December 2008).

 

 

 

 

 

³

The test may be carried out at your doctor's office, in a clinic or at a hospital. It takes about an hour.

 

 

 

 

 

Source:
Cancer Research UK.
Bowel cancer tests.
September 2008. Available at http://www.cancerhelp.org.uk/help/default.asp?page=2819 (accessed on 11 December 2008).

 

 

 

 

 

²

Your whole bowel needs to be empty before this test. You will be given a list of things to do to empty your bowel.

You may need to:

 

 

 

 

 

Source:
Cancer Research UK.
Bowel cancer tests.
September 2008. Available at http://www.cancerhelp.org.uk/help/default.asp?page=2819 (accessed on 11 December 2008).

 

 

 

 

 

²

Just before the test, you will probably be given painkillers and a medicine to make you sleepy (a sedative). This is to make the test less uncomfortable. If you don't want to take a sedative, you need to talk to the doctor beforehand.

 

 

 

 

 

Source:
Cancer Research UK.
Bowel cancer tests.
September 2008. Available at http://www.cancerhelp.org.uk/help/default.asp?page=2819 (accessed on 11 December 2008).

 

 

 

 

 

²

You lie on your side while the doctor slides the tube through your anus and up into your bowel. The light inside the tube helps the doctor to see any problem areas or swelling.

 

 

 

 

 

Source:
Cancer Research UK.
Bowel cancer tests.
September 2008. Available at http://www.cancerhelp.org.uk/help/default.asp?page=2819 (accessed on 11 December 2008).

 

 

 

 

 

²

During the exam, the doctor can remove any polyps and collect samples of any cells that look unusual to examine later.

 

 

 

 

 

Source:
Centers for Disease Control and Prevention.
Colorectal cancer screening.
February 2007. Available at http://www.cdc.gov/cancer/colorectal/basic_info/screening/tests.htm (accessed on 11 December 2008).

 

 

 

 

 

³

You should be able to go home a couple of hours after the test. You shouldn't drive for a few hours after taking a sedative, so you may need someone to drive you home.

 

 

 

 

 

Source:
Cancer Research UK.
Bowel cancer tests.
September 2008. Available at http://www.cancerhelp.org.uk/help/default.asp?page=2819 (accessed on 11 December 2008).

 

 

 

 

 

²

Colonoscopy is a very thorough test for colon and rectal cancer, because it can see the full length of the bowel. That's why doctors use it if you have had a positive result on another test. But it may not find all small polyps and cancers.

There is a very small risk that the colonoscope will tear the bowel wall.

 

 

 

 

 

Source:
National Cancer Institute.
Colorectal cancer screening.
October 2008. Available at http://www.cancer.gov/cancertopics/factsheet/detection (accessed on 10 December 2008).

 

 

 

 

 

¹ This happens in only 1 in every 800 tests. But it can be serious. If it happens, you need an emergency operation to repair your bowel wall and strong antibiotics to fight any infection caused by the injury.

 

 

 

 

 

Source:
Cancer Research UK.
Bowel cancer tests.
September 2008. Available at http://www.cancerhelp.org.uk/help/default.asp?page=2819 (accessed on 11 December 2008).

 

 

 

 

 

²

This is when doctors take

 

 

 

 

 

X-ray
X-rays are pictures taken of the inside of your body. They are done by passing very small amounts of radiation through your body and onto film. X-rays can also be used as a treatment, such as in radiation therapy for cancer.

 

 

 

 

 

X-rays of the whole bowel, using a liquid that makes things easier to see on X-ray.

A nurse will pass a thick white liquid into your rectum through a tube. The liquid contains a chemical called barium. The barium sticks to the lining of your bowel and helps it show up more clearly on the X-ray. You have to hold the liquid inside your rectum until the X-rays have been taken.

 

 

 

 

 

Source:
Cancer Research UK.
Bowel cancer tests.
September 2008. Available at http://www.cancerhelp.org.uk/help/default.asp?page=2819 (accessed on 11 December 2008).

 

 

 

 

 

² The test is normally done in a radiology clinic or at a hospital.

You will need to empty your bowels beforehand. You'll need to:

 

 

 

 

 

Source:
Cancer Research UK.
Bowel cancer tests.
September 2008. Available at http://www.cancerhelp.org.uk/help/default.asp?page=2819 (accessed on 11 December 2008).

 

 

 

 

 

²

After the test you may be

 

 

 

 

 

constipated
When you're constipated, you have difficulty passing stools (feces). Your bowel movements may be dry and hard. You may have fewer bowel movements than usual, and it may be a strain when you try to go.

 

 

 

 

 

constipated, which means you find it difficult to pass stools. Your first couple of stools after the test will be white. This is nothing to worry about, and things will return to normal after the white liquid is out of your body.

 

 

 

 

 

Source:
Cancer Research UK.
Bowel cancer tests.
September 2008. Available at http://www.cancerhelp.org.uk/help/default.asp?page=2819 (accessed on 11 December 2008).

 

 

 

 

 

²

This test lets the doctor see your whole bowel. It can be uncomfortable and tiring, but it doesn't harm your bowel. But it may not find some small polyps and cancers. Sometimes it gives false positive results (this means you don't have cancer, but the test results say you do). With this test, the doctor can't remove polyps or take away abnormal-looking cells to examine later.

 

 

 

 

 

Source:
National Cancer Institute.
Colorectal cancer screening.
October 2008. Available at http://www.cancer.gov/cancertopics/factsheet/detection (accessed on 10 December 2008).

 

 

 

 

 

¹

This is a new test that is sometimes used instead of the double-contrast barium enema test. But it is not yet available everywhere. Other names for it include virtual colonoscopy and computed tomographic colonography.

It uses a computer to put together scans to build up a picture of the inside of your bowel.

You have to empty your bowel beforehand, just as you do for the barium enema. A little air is pumped into your bowel to show up the bowel wall more clearly, and then pictures of the bowel are taken with a computed tomography scanner.

 

 

 

 

 

Source:
Cancer Research UK.
Bowel cancer tests.
September 2008. Available at http://www.cancerhelp.org.uk/help/default.asp?page=2819 (accessed on 11 December 2008).

 

 

 

 

 

²

This test may be less uncomfortable than a colonoscopy or a barium enema, and it doesn't harm your bowel. But the doctor can't remove polyps or abnormal-looking cells during the test.

 

 

 

 

 

Source:
National Cancer Institute.
Colorectal cancer screening.
October 2008. Available at http://www.cancer.gov/cancertopics/factsheet/detection (accessed on 10 December 2008).

 

 

 

 

 

¹

This is a new kind of home testing kit for blood in stools. The fecal occult blood test (FOBT) looks for any blood in your stool. This test looks for a particular type of blood that is more likely to mean cancer. However, like the FOBT, it can only find cancers that are bleeding.

 

 

 

 

 

Source:
American Cancer Society.
Colon and rectum cancer: can colorectal polyps and cancer be found early?
May 2008. Available at http://www.cancer.org (accessed on 11 December 2008).

 

 

 

 

 

⁵

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