NCCN Guidelines for Patients™: Colon Cancer
Part 2: About colon cancer
Screening tests for colon cancer include both structural
tests and stool tests. Structural tests find polyps and small
tumors using imaging machines. Stool tests are used to
find signs of cancer but don’t find the actual tumor.
The tests suggested by the NCCN Guidelines Panel
include a colonoscopy, flexible sigmoidoscopy, and
guaiac stool test. A barium enema is only suggested if you
are unable to have a colonoscopy or your colonoscopy
can’t be completed. There is growing interest in a virtual
colonography. However, there is disagreement among
doctors about using it as a primary screening test.
A colonoscopy is the most complete
screening test. Your doctor can see your entire large
intestine and remove any polyps at one visit.
A colonoscopy is the preferred screening test of
To prepare for the test, your doctor may place you on
a liquid diet for 1 to 3 days. You may also be given a
laxative or an enema to clean your colon the night before
the test. Right before the test, you may be given drugs to
help you relax and to lessen any pain. You will be asked
to wear a hospital gown and lie on your side during the
test (Figure 6).
A colonoscope will be inserted into your anus and gently
guided through your large intestine. To see the colon
better, the colonoscope pumps gas into your colon to
make it bigger. You may be asked to shift a little to help
your doctor guide the colonoscope. The colonoscope
takes pictures that can be seen on a computer. If a polyp
is found, the colonoscope may have a tool to remove it.
A colonoscopy takes about 30 to 60 minutes. Afterward,
you may stay at the hospital or outpatient clinic for
another hour for the drugs to wear off. However, you’ll
still need someone to drive you home. The next day, you
are likely to feel normal. If you have severe pain, bloody
stools, or weakness, contact your doctor.
Structural screening test
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