EDUCATIONL SERIES: Colen Cancer
What is cancer of the colon?
Cancer of the colon, a common form of cancer, is a disease in which
cancer (malignant)
cells are found in the tissues of the colon. The colon is part of the
body's digestive system.
The purpose of the digestive system is to remove nutrients (vitamins,
minerals,
carbohydrates, fats, proteins, and water) from the foods eaten and to
store the waste until
it passes out of the body. 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.
Genes are markers in cells associated with hereditary traits. Abnormal
genes have been
found in patients with some forms of colon and rectal cancer. Tests are
being developed to
determine who carries these genes long before cancer appears.
Screening tests (such as a 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; who have had small noncancerous growths (polyps)
in the colon; or
who have a history of ulcerative colitis (ulcers in the lining of the
large intestines). A doctor
may order these tests to look for cancer if there is 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, wearing thin gloves, puts a greased finger into
the rectum and
gently feels for lumps. The doctor may then check the material collected
from the rectum
to see if there is any blood in it.
The doctor may also want to look inside the rectum and lower colon with
a special
instrument called a sigmoidoscope or a proctosigmoidoscope. This
examination, called a
proctoscopy or procto examination, finds about half of all colon and
rectal cancers. The
test is usually done in a doctor's office. Some pressure may be felt,
but usually with no
pain.
The doctor may also want to look inside the rectum and the entire colon
(colonoscopy)
with a special tool called a colonoscope. This test is also done in a
doctor's office. Some
pressure may be felt, but 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 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 colon or if it has
spread to other places)
and the patient's general state of health. After treatment, a blood test
(to measure amounts
of carcinoembryonic antigen or CEA in the blood) and x-rays may be done
to see if the
cancer has come back.
STAGE EXPLANATION
Stages of cancer of the colon
Once cancer of the colon is found (diagnosed), more tests will be done
to find out if
cancer cells have spread to other parts of the body (staging). A doctor
needs to know the
stage of the disease to plan treatment. The following stages are used
for cancer of the
colon:
Stage 0 or carcinoma in situ
Stage 0 cancer of the colon is very early cancer. The cancer is found
only in the innermost
lining of the colon.
Stage I
The cancer has spread beyond the innermost lining of the colon to the
second and third
layers and involves the inside wall of the colon, but has not spread to
the outer wall of the
colon or outside the colon.
Stage I colon cancer is sometimes called Dukes A colon cancer.
Stage II
Cancer has spread outside the colon to nearby tissue, but it has not
gone into the lymph
nodes. (Lymph nodes are small, bean-shaped structures that are found
throughout the
body. They produce and store cells that fight infection.)
Stage II colon cancer is sometimes called Dukes B colon cancer.
Stage III
Cancer has spread to nearby lymph nodes, but it has not spread to other
parts of the
body. (Lymph nodes are small, bean-shaped structures that are found
throughout the
body. They produce and store cells that fight infection.)
Stage III colon cancer is sometimes called Dukes C colon cancer.
Stage IV
Cancer has spread to other parts of the body.
Stage IV colon cancer is sometimes called Dukes D colon cancer.
Recurrent
Recurrent disease means that the cancer has come back (recurred) after
it has been
treated. It may come back in the colon or in another part of the body.
Recurrent cancer of
the colon is often found in the liver and/or lungs.
TREATMENT OPTION OVERVIEW
How cancer of the colon is treated
There are treatments for all patients with cancer of the colon. Three
kinds of treatments are
available:
surgery (taking out the cancer)
radiation therapy (using high-dose x-rays or other high-energy rays
to kill cancer
cells)
chemotherapy (using drugs to kill cancer cells)
Surgery is the most common treatment of all stages of cancer of the
colon. A doctor may
take out the cancer from the colon using one of the following:
If the cancer is found at a very early stage, the doctor may take
out the
cancer without cutting into the abdomen. Instead, the doctor may
put a
tube through the rectum into the colon and cut the tumor out. This
is
called a local excision. If the cancer is found in a small bulging
piece of
tissue (called a polyp), the operation is called a polypectomy.
If the cancer is larger, the doctor will take out the cancer and a
small
amount of healthy tissue around it (bowel or colon resection). The
healthy
parts of the colon are then sewn together (anastomosis). The doctor
will
also take out lymph nodes near the intestine and look at them under
the
microscope to see if they contain cancer.
If the doctor is not able to sew the colon back together, he or she
will
make an opening (stoma) on the outside of the body for waste to
pass out of
the body. This is called a colostomy. Sometimes, the colostomy is
only
needed until the colon has healed, and then it can be reversed.
However,
the doctor may have to take out the entire lower colon and the
colostomy is
permanent. If a patient has a colostomy, a special bag will need to
be worn
to collect body wastes. This special bag, which sticks to the skin
around
the stoma with a special glue, can be thrown away after it is used.
This bag
does not show under clothing, and most people take care of these
bags
themselves.
Radiation therapy is the use of x-rays or other high-energy rays to kill
cancer cells and
shrink tumors. Radiation may come from a machine outside the body
(external radiation
therapy) or from putting materials that contain radiation through thin
plastic tubes (internal
radiation therapy) in the intestine area. Radiation can be used alone or
in addition to
surgery and/or chemotherapy.
Chemotherapy is the use of drugs to kill cancer cells. Chemotherapy may
be taken by pill,
or it may be put into the body by inserting a needle into a vein. A
patient may be given
chemotherapy through a tube that will be left in the vein while a small
pump gives the
patient constant treatment over a period of weeks. Chemotherapy is
called a systemic
treatment because the drug enters the bloodstream, travels through the
body, and can kill
cancer cells outside the colon. If the cancer has spread to the liver,
the patient may be
given chemotherapy directly into the artery going to the liver.
If the doctor removes all the cancer that can be seen at the time of the
operation, the
patient may be given chemotherapy after surgery to kill any cancer cells
that are left.
Chemotherapy given after an operation to a person who has no cancer
cells that can be
seen is called adjuvant chemotherapy.
Biological treatment tries to get the body to fight cancer. It uses
materials made by the
body or made in a laboratory to boost, direct, or restore the body's
natural defenses
against disease. Biological treatment is sometimes called biological
response modifier
(BRM) therapy or immunotherapy.
Treatment by stage
Treatments for cancer of the colon depend on the stage of the disease
and the patient's
general health.
Standard treatment may be considered because of its effectiveness in
patients in past
studies, or participation in a clinical trial may be considered. Not all
patients are cured with
standard therapy and some standard treatments may have more side effects
than are
desired. For these reasons, clinical trials are designed to find better
ways to treat cancer
patients and are based on the most up-to-date information. Clinical
trials are ongoing in
most parts of the country for most stages of cancer of the colon. To
learn more about
clinical trials, call the Cancer Information Service at 1-800-4-CANCER
(1-800-422-6237); TTY at 1-800-332-8615.
STAGE 0 COLON CANCER
Treatment may be one of the following:
1. Local excision or simple polypectomy to remove all the cancer.
2. Bowel resection.
STAGE I COLON CANCER
Treatment is usually surgery (bowel resection) to remove the cancer and
join the cut ends
of the bowel.
STAGE II COLON CANCER
Treatment may be one of the following:
1. Treatment is usually surgery (bowel resection) to remove the
cancer.
2. Clinical trials of chemotherapy, radiation therapy, or
biological therapy following
surgery.
3. If the tumor has spread to nearby tissue, a patient may also
receive
chemotherapy and/or radiotherapy following surgery.
STAGE III COLON CANCER
Treatment may be one of the following:
1. Treatment is usually surgery (bowel resection) to remove the
cancer followed by
chemotherapy.
2. Clinical trials of chemotherapy, radiation therapy, and/or
biological therapy
following surgery.
STAGE IV COLON CANCER
Treatment may be one of the following:
1. Surgery (bowel resection) to remove the cancer or to make the
colon go around
the cancer so that it can still work.
2. Surgery to remove parts of other organs such as the liver,
lungs, and ovaries,
where the cancer may have spread.
3. Radiation therapy to relieve symptoms.
4. Chemotherapy to relieve symptoms.
5. Clinical trials of chemotherapy or biological therapy.
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