Colon Cancer Screening (cont.)
Screening recommendations for individuals with
average risk of colon cancer
The life-time
risk for an adult American
to develop colorectal cancer is approximately 6%. Fecal occult
blood tests
and flexible sigmoidoscopic examinations are the recommended screening tests
for these
individuals at average risk for developing colorectal
cancer.
These tests are designed to detect and remove precancerous polyps and
identify early
cancers in order to decrease mortality from colorectal cancer.
Fecal occult blood testing and sigmoidoscopy are
affordable, easy to perform, and comfortable for
healthy
individuals.
Fecal occult blood tests
Fecal occult
blood tests are chemical tests
that are
performed on samples of stool to detect the presence
of "occult"
blood (amounts of blood that are so small that
they cannot be seen with the naked eye). These tests usually
are begun at age 40 and then are repeated annually along with a digital rectal examination that is performed by a doctor. The use of fecal occult
blood tests is
based on the observation that slow bleeding from colon polyps
or cancers
can cause small amounts of blood to mix with the colonic contents. (This sometimes can lead to an
iron
deficiency anemia .) Since the small amounts of blood are not visible
to the naked eye, sensitive chemical tests are needed to
detect the traces of
blood in the stool.
Fecal occult blood testing consists of checking for occult blood in 3
stool specimens collected
on special cards at home. To
properly prepare
for collecting the specimens, individuals are asked to abstain
(for
3-5 days before stool collections begin) from certain foods,
medications and
vitamins that can interfere with the accuracy of the
test.
These include certain meats, vitamins (especially vitamin C),
iron,
aspirin, and other antiinflammatory medicines (NSAIDs)
such
as ibuprofen that
are used in treating arthritis and other painful
inflammatory
conditions.
An individual whose stool
specimen
tests positive for occult blood then undergoes a colonoscopic
examination of
the entire colon to look for polyps, cancers, or other conditions
that cause
bleeding (such as abnormal blood vessels and colitis). The majority
(greater
than 90%) of the polyps detected at colonoscopy can be removed
painlessly
and safely during the colonoscopic examination. Polyps so removed
are examined
later under the microscope by a pathologist to determine if they are precancerous. Individuals with
precancerous polyps
have a higher than average risk for developing colon cancer, and are
advised
to return for periodic surveillance colonoscopies (see below). Colon cancers that
are detected at colonoscopy usually are removed surgically though under
certain
circumstances they may be removed at colonoscopy. Precancerous polyps that
are too large
or technically not possible to remove during colonoscopy also are
removed surgically. Several studies have shown that fecal
occult blood
testing can reduce death rates (mortality) from colorectal
cancer by
30-40%.
If no colonic abnormalities are found in an individual whose stool contains
occult blood, consideration then is given to examining the stomach and the small
intestine as sources of bleeding.
Next: Flexible sigmoidoscopy »
- diatrizoate meglumine and diatrizoate sodium-solution, Gastrografin, MD-Gastroview - Consumer information about the medication DIATRIZOATE MEGLUMINE AND DIATRIZOATE SODIUM - SOLUTION (Gastrografin, MD-Gastroview), includes side effects, drug interactions, recommended dosages, and storage information. Read more about the prescription drug DIATRIZOATE MEGLUMINE AND DIATRIZOATE SODIUM - SOLUTION.
- Colonoscopy - Learn about the colonscopy procedure, what it is, why it is performed, preparation, complications, alternatives and the after effects of the screening exam on MedicineNet.com
- Abdominal Pain - Learn about abdominal pain (pain in the stomach / abdomen) including causes, symptoms, how abdominal pain is diagnosed, and how abdominal pain is treated.
Latest Medical News
Cancer RSS