|
This section begins with a discussion of the tests that can be
used
to look for colorectal polyps and cancer. This is followed by a
discussion of current American Cancer Society screening guidelines for
colorectal cancer.
Colorectal cancer screening tests
Screening is the process of looking for cancer in people who
have no
symptoms of the disease. There are several different tests that can be
used to screen for colorectal cancers. These tests can be divided into
2 broad groups:
- Tests that
can find both colorectal polyps and cancer: These
tests look at the structure of the colon itself to find any abnormal
areas. This is done either with a scope inserted into the rectum or
with special imaging (x-ray) tests. Polyps found before they become
cancerous can be removed, so these tests may prevent colorectal cancer.
Because of this, these tests are preferred if they are available and
you are willing to have them.
- Tests that
mainly find cancer: These
involve testing the stool (feces) for signs that cancer may be present.
These tests are less invasive and easier to have done, but they are
less likely to detect polyps.
These tests as well as others can also be used when people
have symptoms of colorectal cancer and other digestive diseases.
Tests that can find both colorectal polyps
and cancer
Flexible sigmoidoscopy
During this test, the doctor looks at part of the colon and
rectum
with a sigmoidoscope -- a flexible, lighted tube about the thickness of
a finger with a small video camera on the end. It is inserted through
the rectum and into the lower part of the colon. Images from the scope
are viewed on a display monitor.
Using the sigmoidoscope, your doctor can view the inside of
the
rectum and part of the colon to detect (and possibly remove) any
abnormality. Because the sigmoidoscope is only 60 centimeters (about 2
feet) long, the doctor is able to see the entire rectum but less than
half of the colon with this procedure.
Before the test:
You will
need to have a bowel preparation to clean out your lower colon. The
colon and rectum must be empty and clean so your doctor can view the
lining of the sigmoid colon and rectum. Your doctor will give you
specific instructions to follow. Be sure your doctor is aware of any
medicines you are taking, as you may need to change how you take them
before the test. You may be asked to follow a special diet (such as
drinking only clear liquids) for a day before the exam. You may also be
asked to use enemas or to use strong laxatives to clean out your colon
before the exam.
During the test:
A
sigmoidoscopy usually takes 10 to 20 minutes. Most people do not need
to be sedated for this test, but this may be an option you can discuss
with your doctor. Sedation may make the test less uncomfortable, but it
requires some time to recover from, as well as having someone with you
to take you home after the test.
You will likely be placed on a table on your left side with
your
knees positioned near your chest. Your doctor should do a digital
rectal exam (DRE) before inserting the sigmoidoscope. The sigmoidoscope
is lubricated to make it easier to insert into the rectum. The scope
may feel cold. The sigmoidoscope may stretch the wall of the colon,
which may cause bowel spasms or lower abdominal pain. Air will be
placed into the sigmoid colon through the sigmoidoscope so the doctor
can see the colon better. During the procedure, you might feel pressure
and slight cramping in your lower abdomen. To ease discomfort and the
urge to have a bowel movement, it helps to breathe deeply and slowly
through your mouth. You will feel better after the test once the air
leaves your colon.
If a small polyp is found during the test your doctor may
remove it
with a small instrument passed through the scope. The polyp will be
sent to a lab to be looked at by a pathologist. If a pre-cancerous
polyp (an adenoma) or colorectal cancer is found during the test, you
will need to have a colonoscopy at a later date to look for polyps or
cancer in the rest of the colon.
Possible
complications and side effects: This
test may be uncomfortable because of the air put into the colon, but it
should not be painful. Be sure to let your doctor know if you feel pain
during the procedure. You may see a small amount of blood in your first
bowel movement after the test. Significant bleeding and puncture of the
colon are possible complications, but they are very uncommon.
Colonoscopy
For this test, the doctor looks at the entire length of the
colon
and rectum with a colonoscope, which is basically a longer version of a
sigmoidoscope. It is inserted through the rectum into the colon. The
colonoscope has a video camera on the end that is connected to a
display monitor so the doctor can see and closely examine the inside of
the colon. Special instruments can be passed through the colonoscope to
remove (biopsy) any suspicious looking areas such as polyps, if needed.
Colonoscopy may be done in a hospital outpatient department,
in a clinic, or in a doctor's office.
Before the test:
Be sure
your doctor is aware of any medicines you are taking, as you may need
to change how you take them before the test. The colon and rectum must
be empty and clean so your doctor can view their inner linings during
the test. You will need to take laxatives (liquids, pills, or both) the
day before the test and possibly an enema that morning. Your doctor
will give you specific instructions. It is important to read these
carefully a few days ahead of time, since you may need to shop for
special supplies and get laxatives from a pharmacy. If you are not sure
about any of the instructions, call the doctor's office and go over
them step by step with the nurse. Many people consider the bowel
preparation to be the most unpleasant part of the test, as it usually
requires you to be in the bathroom quite a bit.
You may be given other instructions as well. For example, your
doctor may instruct that you drink only clear liquids (water, apple or
cranberry juice, and any gelatin except red or purple) for a day or 2
before the exam. Plain tea or coffee with sugar is usually okay, but no
milk or creamer is allowed. Clear broth, ginger ale, and most soft
drinks or sports drinks are usually allowed unless they have red or
purple food colorings, which could be mistaken for blood in the colon.
You will likely also be told not to eat or drink anything
after
midnight the night before your test. If you normally take prescription
medicines in the mornings, talk with your doctor or nurse about how to
manage them for the day.
You may need to arrange for someone to drive you home from the
test
because the sedative used during the test can affect your ability to
drive. Depending on the medicines that are used, some doctors require
that someone drive you home.
During the test:
The test
itself usually takes about 30 minutes, although it may take longer if a
polyp is found and removed. Before the colonoscopy begins, you will be
given a sedating medicine (usually through your vein) to make you feel
comfortable and sleepy during the procedure. You will probably be
awake, but you may not be aware of what is going on and may not
remember the procedure afterward. Most people will be fully awake by
the time they get home from the test.
During the procedure, you will be placed on your side with
your
knees flexed and a drape will cover you. Your blood pressure, heart
rate, and breathing rate will be monitored during and after the test.
Your doctor should do a digital rectal exam (DRE) before
inserting
the colonoscope. The colonoscope is lubricated so it can be easily
inserted into the rectum. Once in the rectum, the colonoscope is passed
all the way to the beginning of the colon, called the cecum. If you are
not sedated, you may feel an urge to have a bowel movement when the
colonoscope is inserted or pushed further up the colon. To ease any
discomfort it may help to breathe deeply and slowly through your mouth.
The colonoscope will deliver air into the colon so that it is easier
for the doctor to see the lining of the colon and use the instruments
to perform the test. Suction will be used to remove any blood or liquid
stools.
The doctor will look at the inner walls of the colon as he or
she
slowly withdraws the colonoscope. If a small polyp is found, the doctor
may remove it. Some small polyps may eventually become cancerous. For
this reason, they are usually removed. This is usually done by passing
a wire loop through the colonoscope to cut the polyp from the wall of
the colon with an electrical current. The polyp can then be sent to a
lab to be checked under a microscope to see if it has any areas that
have changed into cancer.
If your doctor sees a larger polyp or tumor or anything else
abnormal, a biopsy may be done. For this procedure, a small piece of
tissue is taken out through the colonoscope. The tissue is looked at
under a microscope to determine if it is a cancer, a benign
(non-cancerous) growth, or a result of inflammation.
Possible side
effects and complications: The
bowel preparation before the test can be unpleasant. The test itself
may be uncomfortable, but the sedative usually prevents this, and most
people feel normal once the effects of the sedative wear off. Some
people may have gas pains or cramping for a while after the test.
In some cases, people may have low blood pressure or changes
in
heart rhythms due to the sedation during the test, although these are
rarely serious.
If a polyp is removed or a biopsy is done during the
colonoscopy,
you may notice some blood in your stool for a day or 2 after the test.
Significant bleeding is slightly more likely with colonoscopy than with
sigmoidoscopy, but it is still uncommon. In rare cases, continued
bleeding might require treatment.
Although colonoscopy is a safe procedure, on rare occasions
the
colonoscope can puncture the wall of the colon or rectum. This is
called a perforation. It can be a serious complication and at times
requires surgical repair. Talk to your doctor about the risk of this
complication.
Double-contrast barium enema
The double-contrast barium enema (DCBE) is also called an
air-contrast barium enema or a barium enema with air contrast.
It is
basically a type of x-ray test. Barium sulfate, which is a chalky
liquid, and air are used to outline the inner part of the colon and
rectum to look for abnormal areas on x-rays. If suspicious areas are
seen on this test, a colonoscopy will be needed to explore them
further.
Before the test:
As with colonoscopy, it is very important that the
colon and rectum are empty and clean so your doctor can see them during
the test. Your doctor will give you specific instructions on preparing
for the test. Be sure to follow them. For example, you may be asked to
clean your bowel the night before with laxatives and/or take an enema
the morning of the exam. You will likely be asked to follow a clear
liquid diet for a day or 2 before the procedure. You may also be told
to avoid eating or drinking dairy products the day before the test, and
to not eat or drink anything after midnight on the night before the
procedure. Many people consider the bowel preparation to be the most
unpleasant part of the test, as it usually requires you to be in the
bathroom quite a bit.
During the test:
The procedure takes about 30 to 45 minutes, and it
does not require sedation. For this test, you lie on a table on your
side in an x-ray room. A small, flexible tube is inserted into the
rectum, and barium sulfate is pumped in to partially fill and open up
the colon. When the colon is about half-full of barium, you are turned
on the x-ray table so the barium spreads throughout the colon. Then air
is pumped into the colon through the same tube to make it expand. This
may cause some discomfort, and you may feel the urge to have a bowel
movement.
X-ray pictures of the lining of your colon are then taken,
allowing
the doctor to identify polyps or cancers. You may be asked to change
positions so that different views of the colon and rectum can be seen
on the x-rays.
If polyps or other suspicious areas are seen on this test, a
colonoscopy will likely be needed to remove them or to explore them
fully.
Possible side
effects and complications: You may have bloating or
cramping after the test, and will likely feel the need to empty your
bowels soon after the test is done. The barium can cause constipation
for a few days, and your stool may appear grey or white until the
barium leaves the body. There is a very small risk that inflating the
colon with air could injure or puncture the colon, but this risk is
thought to be much less than with colonoscopy.
CT colonography (virtual colonoscopy)
This test is an advanced type of computed tomography (CT or
CAT)
scan of the colon and rectum. A CT scan is an x-ray test that produces
detailed cross-sectional images of your body. Instead of taking one
picture, like a regular x-ray, a CT scanner takes many pictures as it
rotates around you while you lie on a table. A computer then combines
these pictures into images of slices of the part of your body being
studied. For CT colonography, special computer programs create both two
dimensional x-ray pictures and a three-dimensional "fly-through" view
of the inside of the colon and rectum, which allows the doctor to look
for polyps or cancer.
This test may be especially useful for some people who can't
have or
don't want to have more invasive tests such as colonoscopy. It can be
done fairly quickly and does not require sedation. But even though this
test is not invasive like colonoscopy, it still requires the same type
of bowel preparation and uses a tube placed in the rectum (similar to
the tube used for barium enema) to fill the colon with air. Another
possible drawback is that if polyps or other suspicious areas are seen
on this test, a colonoscopy will still likely be needed to remove them
or to explore them fully.
Before the test:
It is important that the colon and rectum are
emptied before this test to provide the best images. Because of this,
the preparation for this test is similar to that for a double contrast
barium enema or colonoscopy. You will likely be told to follow a clear
liquid diet for a day or 2 before the test. You will also be given
instructions for taking strong laxatives and/or enemas the night before
or morning of the exam. This will probably require you to be in the
bathroom quite a bit.
During the test:
This test is done in a special room with a CT
scanner, and takes about 10 minutes. You may be asked to drink a
contrast solution before the test to help "tag" any remaining stool in
the colon or rectum, which helps the doctor when looking at the test
images. You will be asked to lie in a thin table that is part of the CT
scanner, and will have a small, flexible tube inserted into your
rectum. Air is pumped through the tube into the colon to expand it to
provide better images. The table then slides into the CT scanner, and
you will be asked to hold your breath while the scan takes place. You
will likely have 2 scans: one while you are lying on your back and one
while you are on your stomach. Each scan typically takes only about 10
to 15 seconds.
Possible side
effects and complications: There are usually very few
side effects after CT colonography. You may feel bloated or have cramps
because of the air in the colon, but this should go away once the air
passes from the body. There is a very small risk that inflating the
colon with air could injure or puncture the colon, but this risk is
thought to be much less than with colonoscopy.
Tests that mainly find colorectal cancer
These tests examine the stool to look for signs of cancer.
Most
people find these tests to be easier because they are not invasive and
can often be done at home. But they are not as good at detecting polyps
as the tests described above, and a positive result on one of these
screening tests will likely require a more invasive test such as
colonoscopy.
Fecal occult blood test
The fecal occult blood test (FOBT) is used to find occult
(hidden)
blood in feces. The idea behind this test is that blood vessels at the
surface of larger colorectal polyps or cancers are often fragile and
easily damaged by the passage of feces. The damaged vessels usually
release a small amount of blood into the feces, but only rarely is
there enough bleeding to be noticeable in the stool.
The FOBT detects blood in the stool through a chemical
reaction.
This test cannot tell whether the blood is from the colon or from other
portions of the digestive tract (such as the stomach). If this test is
positive, a colonoscopy is needed to see if there is a cancer, polyp,
or other cause of bleeding such as ulcers, hemorrhoids, diverticulosis
(tiny pouches that form at weak spots in the colon wall), or
inflammatory bowel disease (colitis).
This screening test is done with a take-home kit that you can
use in
the privacy of your own home. An
FOBT done during a digital rectal exam
in the doctor's office is not sufficient for screening. In
order to be
beneficial the test must be repeated every year.
People having this test will receive a kit with instructions
from
their doctor's office or clinic. The kit will explain how to take a
stool or feces sample at home (usually specimens from 3 consecutive
bowel movements that are smeared onto small squares of paper). The kit
should then be returned to the doctor's office or medical lab (usually
within 2 weeks) for testing. See below for more details.
Before the test:
Some foods or drugs can affect the test, so your
doctor may suggest that you try to avoid the following before this
test:
- non-steroidal anti-inflammatory drugs (NSAIDs), such as
ibuprofen (Advil), naproxen (Aleve), or aspirin (more than 1 adult
aspirin per day), for 7 days before testing. (They can cause bleeding,
which can lead to a false-positive result.) Acetaminophen (Tylenol) can
be taken as needed.
- vitamin C in excess of 250 mg daily from either supplements
or citrus fruits and juices for 3 days before testing. (This can affect
the chemicals in the test and make it show negative.)
- red meats (beef, lamb, or liver) for 3 days before testing
(Components of blood in the meat may cause the test to show positive.)
Some people who are given the test never do it or don't give
it to
their doctor because they worry that something they ate may interfere
with the test. For this reason, many doctors tell their patients it
isn't essential to follow any restrictions in their diet. The most
important thing is to get the test done. People should try to avoid
taking aspirin or related drugs for minor aches. But if you take these
medicines daily for heart problems or other conditions, don't stop them
for this test without approval from your doctor.
Collecting the samples: Have all of your supplies ready and in
one
place. Supplies will include a test kit, test cards, either a brush or
wooden applicator, and a mailing envelope. The kit will give you
detailed instructions on how to collect the specimen. The instructions
below can be used as a guide, but your kit instructions might be a
little different. Always follow the instructions on your kit.
- You will need to collect a sample from your bowel movement.
You can place a sheet of plastic wrap loosely across the toilet bowl to
catch the stool or you can use a dry container to collect the stool. Do
not let the stool specimen mix with urine. After you obtain a sample,
you can flush the remaining stool down the toilet.
- Use a wooden applicator or a brush to smear a thin film of
the stool sample onto one of the slots in the test card or slide.
- Next, collect a specimen from a different area of the same
stool and smear a thin film of the sample onto the other slot in the
test card or slide.
- Close the slots and put your name and the date on the test
kit. Store the kit overnight in a paper envelope to allow it time to
dry.
- Repeat the test on your next 2 bowel movements as
instructed.
Most tests require collecting more than one sample from different bowel
movements. This improves the accuracy of the test because many cancers
don't bleed all of time, and blood may not be present in all stool
samples.
- Place the test kit in the mailing pouch provided and return
it to your doctor or lab as soon as possible (but within 14 days of
taking the first sample).
If this test finds blood, a colonoscopy will be needed to look
for
the source. It is not sufficient to simply repeat the FOBT or follow up
with other types of tests.
Fecal immunochemical test
The fecal immunochemical test (FIT), also called an
immunochemical
fecal occult blood test (iFOBT), is a newer kind of test that also
detects occult (hidden) blood in the stool. This test reacts to part of
the human hemoglobin protein, which is found on red blood cells.
The FIT is done essentially the same way as the FOBT, but some
people may find it easier to use because there are no drug or dietary
restrictions (vitamins or foods do not affect the FIT) and sample
collection may take less effort. This test is also less likely to react
to bleeding from parts of the upper digestive tract, such as the
stomach.
As with the FOBT, the FIT may not detect a tumor that is not
bleeding, so multiple stool samples should be tested. And if the
results are positive for hidden blood, a colonoscopy is required to
investigate further. In order to be beneficial the test must be
repeated every year.
Collecting the
samples: Have all of your supplies ready and in one
place. Supplies will include a test kit, test cards, long brushes,
waste bags, and a mailing envelope. The kit will give you detailed
instructions on how to collect the specimen. The instructions below can
be used as a guide, but the instructions on your kit might be a little
different. Always follow the instructions on your kit.
- Flush the toilet before your bowel movement. After you go,
place used toilet paper in the waste bag from the kit, not in the
toilet.
- Brush the surface of the stool with one of the brushes,
then
dip the brush in the toilet water. Dab the end of the brush onto one of
the slots in the test card or slide.
- Close the slot and put your name and the date on the test
kit.
- Repeat the test on your next bowel movement if instructed.
Most tests require collecting more than one sample from different bowel
movements. This improves the accuracy of the test because many cancers
don't bleed all of the time, and blood may not be present in all stool
samples.
- Place the test kit in the mailing envelope provided and
return it to your doctor or lab as soon as possible (but within 14 days
of taking the first sample).
Stool DNA tests
Instead of looking for blood in the stool, these tests look
for
certain abnormal sections of DNA (genetic material) from cancer or
polyp cells. Colorectal cancer cells often contain DNA mutations
(changes) in certain genes. Cells from colorectal cancers or polyps
with these mutations are often shed into the stool, where tests may be
able to detect them.
This is a newer type of test, and the best length of time to
go
between tests is not yet clear. This test is also much more expensive
than other forms of stool testing.
This test is not invasive and doesn't require any special
preparation. But as with other stool tests, if the results are
positive, a colonoscopy is required to investigate further.
People having this test will receive a kit with detailed
instructions from their doctor's office or clinic on how to collect the
specimen. Always follow the instructions on your kit.
This test requires an entire stool sample. It is obtained
using a
special container, which is placed in a bracket that stretches across
the seat of the toilet. You have your bowel movement while sitting on
the toilet, making sure it goes into the container. You then place the
container and an ice pack in a shipping box and close and label the
box. The specimen must be shipped to the lab within 24 hours of having
the bowel movement.
What are some of the pros and cons of these
screening tests?
|
Test
|
Pros
|
Cons
|
|
Flexible sigmoidoscopy
|
Fairly quick and safe
Usually doesn't require full bowel preparation
Sedation usually not used
Does not require a specialist
Done every 5 years
|
Views only about a third of the colon
Can miss small polyps
Can't remove all polyps
May be some discomfort
Done in a doctor’s office, clinic, or
hospital
Very small risk of bleeding, infection, or bowel tear
Colonoscopy will be needed if abnormal
|
|
Colonoscopy
|
Can usually view entire colon
Can biopsy and remove polyps
Done every 10 years
Can diagnose other diseases
|
Can miss small polyps
Full bowel preparation needed
More expensive on a one-time basis than other forms of
testing
Sedation of some kind is usually needed
Will need someone to drive you home
You may miss a day of work
Small risk of bleeding, bowel tears, or infection
|
|
Double contrast barium enema (DCBE)
|
Can usually view entire colon
Relatively safe
Done every 5 years
No sedation needed
|
Can miss small polyps
Full bowel preparation needed
Some false positive test results
Cannot remove polyps during testing
Colonoscopy will be needed if abnormal
|
|
CT colonography (virtual colonoscopy)
|
Fairly quick and safe
Can usually view entire colon
Done every 5 years
No sedation needed
|
Can miss small polyps
Full bowel preparation needed
Some false positive test results
Cannot remove polyps during testing
Colonoscopy will be needed if abnormal
Still fairly new - may be insurance issues
|
|
Fecal occult blood test (FOBT)
|
No direct risk to the colon
No bowel preparation
Sampling done at home
Inexpensive
|
May miss many polyps and some cancers
May produce false-positive test results
May have pre-test dietary limitations
Should be done annually
Colonoscopy will be needed if abnormal
|
|
Fecal immunochemical test (FIT)
|
No direct risk to the colon
No bowel preparation
No pre-test dietary restrictions
Sampling done at home
Fairly inexpensive
|
May miss many polyps and some cancers
May produce false-positive test results
Should be done annually
Colonoscopy will be needed if abnormal
|
|
Stool DNA test
|
No direct risk to the colon
No bowel preparation
No pre-test dietary restrictions
Sampling done at home
|
May miss many polyps and some cancers
May produce false-positive test results
More expensive than other stool tests
Still a fairly new test
Not clear how often it should be done
Colonoscopy will be needed if abnormal
|
American Cancer Society recommendations for
colorectal cancer early detection
People at average risk
The American Cancer Society believes that preventing
colorectal
cancer (and not just finding it early) should be a major reason for
getting tested. Finding and removing polyps keeps some people from
getting colorectal cancer. Tests that have the best chance of finding
both polyps and cancer are preferred if these tests are available to
you and you are willing to have them.
Beginning at age 50, both men and women at average risk for
developing colorectal cancer should use one of the screening tests
below:
Tests that find polyps and cancer
- flexible sigmoidoscopy every 5 years*
- colonoscopy every 10 years
- double-contrast barium enema every 5 years*
- CT colonography (virtual colonoscopy) every 5 years*
Tests that mainly find cancer
- fecal occult blood test (FOBT) every year*,**
- fecal immunochemical test (FIT) every year*,**
- stool DNA test (sDNA), interval uncertain*
*Colonoscopy should be done
if test results are positive.
**For FOBT or
FIT used as a screening test, the take-home multiple
sample method should be used. A FOBT or FIT done during a digital
rectal exam in the doctor's office is not adequate for screening.
In a digital
rectal examination (DRE), a doctor examines your rectum
with a lubricated, gloved finger. Although a DRE is often included as
part of a routine physical exam, it is not recommended as a stand-alone
test for colorectal cancer. This simple test, which is not usually
painful, can detect masses in the anal canal or lower rectum. By
itself, however, it is not a very sensitive test for detecting
colorectal cancer due to its limited reach.
Doctors often find a small amount of stool when doing a DRE.
However, simply checking stool obtained in this fashion for evidence of
bleeding with a FOBT or FIT is not an acceptable method of screening
for colorectal cancer. Research has shown that this type of stool
examination will miss more than 90% of colon abnormalities, including
most cancers.
People at increased or high risk
If you are at an increased risk or high risk of colorectal
cancer,
you should begin colorectal cancer screening before age 50 and/or be
screened more often. The following conditions place you at higher than
average risk:
- a personal history of colorectal cancer or adenomatous
polyps
- a personal history of inflammatory bowel disease
(ulcerative colitis or Crohn's disease)
- a strong family history of colorectal cancer or polyps (see
the section "What
are the risk factors for colorectal cancer?")
- a known family history of hereditary colorectal cancer
syndromes such as familial adenomatous polyposis (FAP) or hereditary
non-polyposis colon cancer (HNPCC)
The table below suggests screening guidelines for those with
increased or high risk
of colorectal cancer based on specific risk
factors. Some people may have more than one risk factor. Refer to the
table below and discuss these recommendations with your doctor. Based
on your situation and any risk factors you may have, your doctor can
suggest the best screening option for you, as well as any changes in
the schedule based on your individual risk.
| Risk Category |
Age to Begin |
Recommended Test(s) |
Comment |
| INCREASED
RISK -- Patients With a History of Polyps on Prior Colonoscopy |
| People with small rectal hyperplastic polyps |
Same as those with average risk
|
Colonoscopy, or other screening options at
regular intervals as for those at average risk |
Those with hyperplastic polyposis syndrome are at
increased risk for adenomatous polyps and cancer and should have more
intensive follow-up.
|
| People with 1 or 2 small (less than 1 cm) tubular
adenomas with low-grade dysplasia |
5 to 10 years after the polyps are removed |
Colonoscopy |
Time between tests should be based on other
factors such as prior colonoscopy findings, family history, and patient
and doctor preferences. |
| People with 3 to 10 adenomas, or a large (1 cm +)
adenoma, or any adenomas with high-grade dysplasia or villous features |
3 years after the polyps are removed |
Colonoscopy |
Adenomas must have been completely removed. If
colonoscopy is normal or shows only 1 or 2 small tubular adenomas with
low-grade dysplasia, future colonoscopies can be done every 5 years. |
| People with more than 10 adenomas on a single exam |
Within 3 years after the polyps are removed |
Colonoscopy |
Doctor should consider possibility of genetic
syndrome (such as FAP or HNPCC). |
| People with sessile adenomas that are removed in
pieces |
2 to 6 months after adenoma removal |
Colonoscopy |
If entire adenoma has been removed, further
testing should be based on doctor’s judgment |
| INCREASED
RISK – Patients With Colorectal Cancer |
| People diagnosed with colon or rectal cancer |
At time of colorectal surgery, or can be 3 to 6
months later if person doesn't have cancer spread that can't be removed |
Colonoscopy to view entire colon and remove all
polyps |
If the tumor presses on the colon/rectum and
prevents colonoscopy, CT colonoscopy (with IV contrast) or DCBE may be
done to look at the rest of the colon. |
| People who have had colon or rectal cancer
removed by surgery |
Within 1 year after cancer resection (or 1 year
after colonoscopy to make sure the rest of the colon/rectum was clear) |
Colonoscopy |
If normal, repeat exam in 3 years. If normal
then, repeat exam every 5 years. Time between tests may be shorter if
polyps are found or there is reason to suspect HNPCC. After low
anterior resection for rectal cancer, exams of the rectum may be done
every 3 to 6 months for the first 2 to 3 years to look for signs of
recurrence. |
| INCREASED
RISK – Patients With a Family History |
| Colorectal cancer or adenomatous polyps in any
first-degree relative before age 60, or in 2 or more first-degree
relatives at any age (if not a hereditary syndrome). |
Age 40, or 10 years before the youngest case in
the immediate family, whichever is earlier |
Colonoscopy |
Every 5 years. |
| Colorectal cancer or adenomatous polyps in any
first-degree relative aged 60 or higher, or in at least 2 second-degree
relatives at any age |
Age 40 |
Same options as for those at average risk. |
Same intervals as for those at average risk. |
| HIGH
RISK |
| Familial adenomatous polyposis (FAP) diagnosed by
genetic testing, or suspected FAP without genetic testing |
Age 10 to 12 |
Yearly flexible sigmoidoscopy to look for signs
of FAP; counseling to consider genetic testing if it hasn't been done |
If genetic test is positive, removal of colon
(colectomy) should be considered. |
| Hereditary non-polyposis colon cancer (HNPCC), or
at increased risk of HNPCC based on family history without genetic
testing |
Age 20 to 25 years, or 10 years before the
youngest case in the immediate family |
Colonoscopy every 1 to 2 years; counseling to
consider genetic testing if it hasn't been done |
Genetic testing should be offered to first-degree
relatives of people found to have HNPCC mutations by genetic tests. It
should also be offered if 1 of the first 3 of the modified Bethesda
criteria is met.1 |
Inflammatory bowel disease
-Chronic ulcerative colitis
-Crohn's disease |
Cancer risk begins to be significant 8 years
after the onset of pancolitis (involvement of entire large intestine),
or 12-15 years after the onset of left-sided colitis |
Colonoscopy every 1 to 2 years with biopsies for
dysplasia |
These people are best referred to a center with
experience in the surveillance and management of inflammatory bowel
disease. |
1The Bethesda
criteria can be found in the "Can
Colorectal Cancer Be Prevented?" section.
Insurance coverage for colorectal cancer
screening
Despite the availability of effective colorectal cancer
screening
tests, not enough people have them. Some factors affecting their use
could include lack of public and health professional awareness of
screening tools, financial barriers, and inadequate health insurance
coverage and/or benefits.
Laws regarding insurance coverage for colorectal cancer
screening
tests vary by state. The same is true of state Medicaid programs. For
people with Medicare, coverage begins at age 50 for the most common
colorectal cancer screening tests.
For more information on insurance coverage for colorectal
cancer
screening tests, please see the separate American Cancer Society
document, Colorectal Cancer: Early
Detection.
Last Medical Review: 05/18/2009 Last Revised: 05/18/2009
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