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Cancer of the rectum, a common form
of cancer, is a disease in which cancer (malignant) cells are found
in the tissues of the rectum. The rectum is part of the body's
digestive system. The digestive system is made up of the esophagus,
stomach, and the small and large intestines. The last 6 feet of
intestine is called the large bowel or colon. The last 8 to 10
inches of the colon is the rectum. The purpose of the digestive
system is to remove nutrients, such as vitamins and minerals, from
food and to store the waste until it passes out of the body.
A doctor should be seen if a person
has a change in bowel habits or if there is any bleeding from the
rectum.
A doctor will usually begin by giving
the patient a rectal examination. In a rectal examination, the
doctor places a gloved, greased finger into the rectum and gently
feels for lumps. The doctor may then check material collected from
the rectum to see if there is any blood in it.
The doctor may want to look inside
the rectum and lower colon with a special instrument called a
sigmoidoscope or proctosigmoidoscope. This examination, called a
proctoscopy or procto examination, finds about half of all colon and
rectal cancers. The doctor may also want to look inside the rectum
and the entire colon (colonoscopy) with a special tool called a
colonoscope. Both examinations are done in a doctor's office. Also,
for both tests, patients may feel some pressure usually with no
pain.
If tissue that is not normal is
found, the doctor will need to cut out a small piece and look at it
under the microscope to see if there are any cancer cells. This is
called a biopsy. Biopsies are usually done during the proctoscopy or
colonoscopy in a doctor's office.
The doctor may also perform a test
called an endorectal ultrasound. This test uses sound from a probe
inserted into the rectum to determine how large the tumor is, and
whether it has spread.
Screening tests (such as the rectal
examination, proctoscopy, and colonoscopy) may be done regularly in
patients who are at higher risk to get cancer. These tests may be
done in patients who are over age 50; who have a family history of
cancer of the colon, rectum, or of the female organs; or who have a
history of ulcerative colitis (ulcers in the lining of the large
intestines).
Other tests are being developed. In
patients with some forms of rectal and colon cancer, abnormal genes
have been found. Genes are markers in cells associated with
hereditary traits. Tests are being developed to determine who
carries these abnormal genes long before cancer appears.
After treatment, blood tests (to
measure amounts of carcinoembryonic antigen or CEA in the blood) and
x-ray tests also may be done to see if the cancer has come back.
The prognosis (chance of recovery)
and choice of treatment depend on the stage of the cancer (whether
it is just in the inner lining of the rectum or if it has spread to
other places) and the patient's general state of health.
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For more information on colorectal
cancer, please visit the Colorectal Cancer Home
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