Colon Cancer Screening

Colorectal Cancer Screening Methods

   click on test name to read more
Type of Test Accuracy How Often (if results are negative) Advantages Disadvantages
Fecal Occult Blood Test
(FOBT)
Does not find any polpys

Finds about 60% of cancers
Once a year Inexpensive, covered by most insurance

Test sample collected in privacy at home

Strong evidence this screening reduces mortality
Limited accuracy

May be unpleasant, you collect your own stool sample

Need to restrict diet for 3 days

If the test shows blood, a followup colonoscopy is needed
Flexible Sigmoidoscopy combined with FOBT Finds 0% of polyps or cancer in the top part of the colon

Finds about 73% of small polyps in the last third of the colon only

Finds about 97% of large polyps in the last third of the colon only

Finds about 85-97% of cancers in the last third of the colon only
FlexSig every 5 years, when combined with yearly FOBT Moderate cost, covered by most insurance

Many primary care physicians can do the test in their office

Evidence suggests this screening reduces mortality
Cannot find cancers in the first third of the colon, where 40% of colon cancers occur

Requires laxative and/or enema preparation

No food on the day of the test

May be embarassing for some people

Could cause mild to moderate discomfort

Small risk of perforation or bleeding

Needs to be combined with FOBT

The FOBT needs to be done once a year

If polyps are found, a full colonoscopy is needed
Air Contrast Barium Enema (ACBE) Finds about 67% of small polyps

Finds about 82% of large polyps

Finds about 84% of cancers
Every 5 years Screens full colon Need to follow a liquid diet for one day before, no food and laxative preparation the day of the test

May be embarassing for some people

Could cause moderate discomfort

A follow-up colonoscopy will need to be done to remove any polyps or cancer the test finds

Does not provide an adequate exam of the rectum and may miss rectal polyps
Colonoscopy Finds about 79% of small polyps

Finds about 85% of large polyps in the entire colon

Finds about 96.7% of cancers
Every 10 years Screens full colon

No discomfort or pain with sedation
Need to follow a liquid diet for one day and laxative preparation before the test

May be embarassing for some people

Small risk of perforation or bleeding

 

Type of Test Accuracy How Often (if results are negative) Advantages Disadvantages
Fecal Occult Blood Test (FOBT) Does not find any polpys

Finds about 60% of cancers
Once a year Inexpensive, covered by most insurance

Test sample collected in privacy at home

Strong evidence this screening reduces mortality
Limited accuracy

May be unpleasant, you collect your own stool sample

Need to restrict diet for 3 days

If the test shows blood, a followup colonoscopy is needed

What is a Fecal Occult Blood Test?
Any blood in your stool or bowel movement could be a sign that you are bleeding from inside your colon or rectum. Colon cancers often bleed so the blood in your stool could be a sign that you have a colon or rectum cancer, however, many things can cause bleeding.

Blood in your stool cannot always be seen with the naked eye. A Fecal Occult Blood Test (FOBT) is a lab test to see if there are traces of blood in your stool.

How to prepare for the test
Your doctor gives you a kit to collect a stool sample at home. You put a small amount of stool on a card and mail it to the lab. Your doctor will tell you how to collect the sample and watch what you eat for three days before the test (for example, no red meat).

The lab sends the FOBT results to your doctor. A positive test does not mean you have colon cancer. If you get a positive test, you will need a colonoscopy to make sure the bleeding is not coming from colon or rectum cancer.

After the test
If you get a negative test, this does not mean you have no colon cancer. The FOBT may not find all cancers. Colon cancers can bleed on and off and you may do the test when the cancer is not bleeding.

Also, the FOBT will not find the small growths (polyps) that usually do not bleed. Finding and removing a polyp before it becomes cancer is a good way to prevent colon cancer.

Fecal Occult Blood Test  |  Flexible Sigmoidoscopy  |  Air Contrast Barium Enema  |  Colonoscopy  |  Back to top

 

Type of Test Accuracy How Often (if results are negative) Advantages Disadvantages
Flexible Sigmoidoscopy with FOBT Finds 0% of polyps or cancer in the top part of the colon

Finds about 73% of small polyps in the last third of the colon only

Finds about 97% of large polyps in the last third of the colon only

Finds about 85-97% of cancers in the last third of the colon only
FlexSig every 5 years, when combined with yearly FOBT Moderate cost, covered by most insurance

Many primary care physicians can do the test in their office

Evidence suggests this screening reduces mortality
Cannot find cancers in the first third of the colon, where 40% of colon cancers occur

Requires laxative and/or enema preparation

No food on the day of the test

May be embarassing for some people

Could cause mild to moderate discomfort

Small risk of perforation or bleeding

Needs to be combined with FOBT

The FOBT needs to be done once a year

If polyps are found, a full colonoscopy is needed

What is a Flexible Sigmoidoscopy?
Flexible Sigmoidoscopy (Flex Sig) allows the doctor to check in the lower part of the colon and rectum for signs of cancer and growths (polyps).

This test is very similar to a colonoscopy but instead of examining the entire colon, the Flex Sig only looks at the last third where most cancers are found. The doctor uses a long flexible camera to look at the inside of your rectum and lower part of the colon. Tissue samples and polyps can be removed at the same time. If lesions are found, you will need a more extensive test which will cause some moderate discomfort without sedation.

How to prepare for the test
Your colon has to be empty for the test so you will not be allowed to eat anything the day before, only liquids, and you will need to take laxatives. The doctor will put small puffs of air inside your colon to expand it and give a better view.

You will not need to be sedated for the Flex Sig because it doesn't go as far up as a colonoscopy does. However, because the Flex Sig doesn’t examine the entire length of your colon, it could miss any polyps or cancers growing in the upper part.

After the test
The air that was puffed inside your colon will need to be passed as gas. The results of the Flex Sig will be mailed to your home about a week after the test. FOBT will need to be repeated every year.

Fecal Occult Blood Test  |  Flexible Sigmoidoscopy  |  Air Contrast Barium Enema  |  Colonoscopy  |  Back to top

 

Type of Test Accuracy How Often (if results are negative) Advantages Disadvantages
Air Contrast Barium Enema (ACBE) Finds about 67% of small polyps

Finds about 82% of large polyps

Finds about 84% of cancers
Every 5 years Screens full colon Need to follow a liquid diet for one day before, no food and laxative preparation the day of the test

May be embarassing for some people

Could cause moderate discomfort

A follow-up colonoscopy will need to be done to remove any polyps or cancer the test finds

Does not provide an adequate exam of the rectum and may miss rectal polyps

What is an Air Contrast Barium Enema (ACBE)?
A barium enema is an x-ray test that looks for things that are wrong in the intestines such as colon cancer. During the test a soft, chalky, liquid dye (called barium) is put in the colon. The dye is also metallic which shows up on an x-ray. The ACBE can find polyps and cancer in the colon but does not examine the rectum.

How to get ready for the test
Before the test your intestines will need to be empty and free of stool. The day before the test you will be put on a liquid diet that includes water, clear juices, Jell-O, and soup broth. After midnight on the day before the test you should not eat or drink anything. Your doctor will tell you to take a laxative the night before the test and you may need to have an enema.

How the test is done
On the day of the test you will have x-rays done to be sure your intestines are empty. An enema tube is put in your rectum and the metallic dye is passed through the tube into your intestines. Air will be puffed into your intestines. Some people will have a moderate amount of discomfort and feel the urge to have a bowel movement as the dye and air are put inside the intestines.

You may be asked to turn in different positions and hold you breath to get the best x-ray pictures. The person taking the x-rays may also press on your stomach to move your colon around to get the best pictures.

After the test
Once the test is done you can go back to your usual diet and regular day. You may be asked to drink extra water for 24 hours after the test. Your stools will be white or pale for several days after the test as your body gets rid of the chalky dye. The results will be mailed to your home about three to five days later.

Fecal Occult Blood Test  |  Flexible Sigmoidoscopy  |  Air Contrast Barium Enema  |  Colonoscopy  |  Back to top

 

Type of Test Accuracy How Often (if results are negative) Advantages Disadvantages
Colonoscopy Finds about 79% of small polyps

Finds about 85% of large polyps in the entire colon

Finds about 96.7% of cancers
Every 10 years Screens full colon

No discomfort or pain with sedation
Need to follow a liquid diet for one day and laxative preparation before the test

May be embarassing for some people

Small risk of perforation or bleeding

What is a colonoscopy?
A colonoscopy is a test that lets the doctor check out the inside of your colon and rectum. Colonoscopy can find and remove any early signs of cancer growths and polyps on the lining of your colon or rectum.

How to get ready for the test
Your colon needs to be completely empty when the colonoscopy is done. You only drink tea, fruit juice, clear soda and Jello (not red Jello) the day before, and you also need to take laxatives and drink nothing after midnight the night before the test.

The doctor will tell you what to do about any daily medications you take. Some medications will need to be stopped five days before: others can be taken with small sips of water early in the morning on the day of the test. You will also need to bring a list of all medications with you and make sure to tell the doctor if you have any health problems.

Although the exam only takes about 45 minutes, you should plan to be at the doctor's office for about four hours. You will feel drowsy after the test and be a little forgetful, and your reflexes will be slower because of the medications used. This means you need to have a friend or family member come with you and drive you home. You will also need to take the day off work but you will be O.K to return to work the next day.

How the test is done
The doctor will give you medications to make you sleepy and drowsy. The medications contain a pain killer and will make you forget most of the exam. Colonoscopy rarely causes much pain.

You will be hooked up to monitors, asked to lay on your side on the examining table, and then the doctor will put a long flexible tube like a telescope into your rectum. This allows the doctor to see inside your entire colon and get tiny samples of tissue (biopsy) or polyps. The doctor puffs a little air into your colon to make it wider and easier to examine. If tissue or polyps are removed they will be sent to the lab to be examined under a microscope.

After the test
After about half an hour, when you feel more awake, you get a snack and the nurse will make sure you can get to the bathroom to pass gas. You may have some cramping and bloating because of the air puffed into you during the exam. This usually goes away within a few hours. You will then change back into your street clothes, get some follow up instructions and leave. For your own safety, you will not be allowed to leave in a cab; you must have someone drive you home.

When you get home you can eat whatever you like. The colonoscopy results will be mailed to your home about a week after the test.

Fecal Occult Blood Test  |  Flexible Sigmoidoscopy  |  Air Contrast Barium Enema  |  Colonoscopy  |  Back to top

 




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