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What is anal cancer?
Anal cancer, an uncommon cancer, is a disease in which cancer (malignant)
cells are found in the anus. The anus is the opening at the end of the rectum
(the end part of the large intestine) through which body waste passes. Cancer in
the outer part of the anus is more likely to occur in men; cancer of the inner
part of the rectum (anal canal) is more likely to occur in women. If the anus is
often red, swollen, and sore, there is a greater chance of getting anal cancer.
Tumors found in the area of skin with hair on it just outside the anus are skin
tumors, not anal cancer.
A doctor should be seen if one or more of the following symptoms appear:
- bleeding from the rectum (even a small amount),
- pain or pressure in the area around the anus,
- itching or discharge from the anus, or
- a lump near the anus.
If there are signs of cancer, a doctor will usually examine the outside part
of the anus and give a patient a rectal examination. In a rectal examination, a
doctor, wearing thin gloves, puts a greased finger into the rectum and gently
feels for lumps. The doctor may also check any material on the glove to see if
there is blood in it. The doctor may give the patient general anesthesia,
medicine that puts patients to sleep, to continue the examination if pain is
felt during it. The doctor may cut out a small piece of tissue and look at it
under a microscope to see if there are any cancer cells. This procedure is
called a biopsy.
The prognosis (chance of recovery) and choice of treatment depend on the
stage of the cancer (whether it is just in the anus or has spread to other
places in the body) and the patient's general health.
Stage Explanation
Stages of anal cancer
Once anal cancer is found (diagnosed), more tests will be done to find out
if cancer cells have spread to other parts of the body. This testing is called
staging. To plan treatment, a doctor needs to know the stage of the disease. The
following stages are used for anal cancer.
Stage 0 or carcinoma in situ
Stage 0 anal cancer is very early cancer. The cancer is found only in the
top layer of anal tissue.
Stage I
The cancer has spread beyond the top layer of anal tissue, is smaller than 2
centimeters in diameter (less than 1 inch), but has not spread to the muscle
tissue of the sphincter.
Stage II
Cancer has spread beyond the top layer of anal tissue and is larger than 2
centimeters in diameter, but has not spread to nearby organs or lymph nodes
(small, bean-shaped structures found throughout the body that produce and store
infection-fighting cells).
Stage IIIA
Cancer has spread to the lymph nodes around the rectum or to nearby organs
such as the vagina or bladder.
Stage IIIB
Cancer has spread to the lymph nodes in the middle of the abdomen or in the
groin, or the cancer has spread to both nearby organs and the lymph nodes around
the rectum.
Stage IV
Cancer has spread to distant lymph nodes within the abdomen or to organs in
other parts of the body.
Recurrent
Recurrent disease means that the cancer has come back (recurred) after it
has been treated. It may come back in the anus or in another part of the body.
Treatment Option Overview
How anal cancer is treated
There are treatments for all patients with anal cancer. Three kinds of
treatment are used:
- Surgery (taking out the cancer in an operation)
- 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 a common way to diagnose and treat anal cancer. A doctor may take
out the cancer using one of the following methods:
- Local resection is an operation that takes out only the
cancer. Often the ring of muscle around the anus that opens and closes it
(the sphincter muscle) can be saved during surgery so that you will be able
to pass the body wastes as before.
- Abdominoperineal resection is an operation in which the doctor
removes the anus and the lower part of the rectum by cutting into the
abdomen and the perineum, which is the space between the anus and the
scrotum (in men) or the anus and the vulva (in women). A doctor will then
make an opening (stoma) on the outside of the body for waste to pass out of
the body. This opening is called a colostomy. Although this operation was
once commonly used for anal cancer, it is not used as much today because
radiation therapy with or without chemotherapy is an equally effective
treatment option but does not require a colostomy. If a patient has a
colostomy, a special bag will need to be worn to collect body wastes. This
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. Lymph nodes may also be
taken out at the same time or in a separate operation (lymph node
dissection).
Radiation therapy uses 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 produce radiation
(radioisotopes) through thin plastic tubes in the area where the cancer cells
are found (internal radiation therapy). Radiation can be used alone or in
addition to other treatments.
Chemotherapy uses drugs to kill cancer cells. Chemotherapy may be taken by
pill, or it may be put into the body by a needle in a vein or muscle.
Chemotherapy is called a systemic treatment because the drugs enter the
bloodstream, travel through the body, and can kill cancer cells throughout the
body. Some chemotherapy drugs can also make cancer cells more sensitive to
radiation therapy. Radiation therapy and chemotherapy can be used together to
shrink tumors and make an abdominoperineal resection unnecessary. When only
limited surgery is required, the sphincter muscle can often be saved.
Treatment by stage
Treatments for anal cancer depend on the type of disease, stage of disease,
and the patient's age and general health.
Standard treatment may be considered, based on its effectiveness in patients
in past studies, or participation in a clinical trial. 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 anal cancer.
Stage 0 Anal Cancer
Treatment will probably be local resection to remove all of the cancer.
Stage I Anal Cancer
Treatment may be one of the following:
Local resection to remove all of the cancer.
Radiation therapy with or without chemotherapy. Some patients
may also receive therapy that involves placing radioactive substances in the
tissues surrounding the cancer to destroy the cancer (interstitial radiation
therapy).
If cancer cells remain following therapy, surgery removing the
anus and lower part of the rectum may be performed. An opening will be made
for waste to pass of out the body (colostomy) into a disposable bag attached
near the colostomy (colostomy bag).
If cancer cells remain following therapy, additional
chemotherapy plus radiation therapy may be performed.
Radiation therapy followed by interstitial radiation therapy.
Stage II Anal Cancer
Treatment may be one of the following:
Local resection to remove all of the cancer.
Radiation therapy plus chemotherapy. Some patients may also
receive therapy that involves placing radioactive substances in the tissues
surrounding the cancer to destroy the cancer (interstitial radiation
therapy).
If cancer cells remain following therapy, surgery removing the
anus and lower part of the rectum may be performed. An opening will be made
for waste to pass of out the body (colostomy) into a disposable bag attached
near the colostomy (colostomy bag).
If cancer cells remain following therapy, additional
chemotherapy plus radiation therapy may be performed.
Stage IIIA Anal Cancer
Treatment may be one of the following:
Radiation therapy plus chemotherapy.
Surgery to remove the lining around the colon and stomach plus
removal of the lymph nodes followed by radiation therapy.
Stage IIIB Anal Cancer
Treatment will probably be radiation therapy plus chemotherapy followed by
surgery. Depending on how much cancer remains following chemotherapy and
radiation, surgery to remove the cancer or surgery to remove the anus and the
lower part of the rectum (abdominoperineal resection) may be done. During
surgery, the lymph nodes in the groin may be removed (lymph node dissection).
Stage IV Anal Cancer
Treatment may be one of the following:
Surgery to relieve symptoms caused by the cancer.
Radiation therapy to relieve symptoms caused by the cancer.
Chemotherapy and radiation therapy to relieve symptoms caused
by the cancer.
A clinical trial evaluating new treatments.
Recurrent Anal Cancer
The choice of treatment will be based on what treatment the patient received
when the cancer was first treated. If the patient was treated with surgery,
radiation therapy may be given if the cancer recurs. If the patient were treated
with radiation, surgery may be used if the cancer recurs. Clinical trials are
studying new chemotherapy drugs with or without radiation therapy. The patient
may also receive additional chemotherapy and radiation therapy.
To Learn More
Call
For more information, U.S. residents may call the National Cancer
Institute's (NCI's) Cancer Information Service toll-free at 1-800-4-CANCER
(1-800-422-6237) Monday through Friday from 9:00 a.m. to 4:30 p.m. Deaf and
hard-of-hearing callers with TTY equipment may call 1-800-332-8615. The call is
free and a trained Cancer Information Specialist is available to answer your
questions.
Web sites and Organizations
The NCI's Cancer.gov Web site provides
online access to information on cancer, clinical trials, and other Web sites and
organizations that offer support and resources for cancer patients and their
families. There are also many other places where people can get materials and
information about cancer treatment and services. Local hospitals may have
information on local and regional agencies that offer information about
finances, getting to and from treatment, receiving care at home, and dealing
with problems associated with cancer treatment.
LiveHelp
The NCI's LiveHelp service, a program available on several of the
Institute's Web sites, provides Internet users with the ability to chat online
with an Information Specialist. The service is available from 9:00 a.m. to 10:00
p.m. Eastern time, Monday through Friday. Information Specialists can help
Internet users find information on NCI Web sites and answer questions about
cancer.
Write
For more information from the NCI, please write to this address:
NCI Public Inquiries Office
Suite 3036A
6116 Executive Boulevard, MSC8322
Bethesda, MD 20892-8322
Listings of clinical trials are included in PDQ and are available online at Cancer.gov.
Descriptions of the trials are available in health professional and patient
versions. Many cancer doctors who take part in clinical trials are also listed
in PDQ. For more information, call the Cancer Information Service 1-800-4-CANCER
(1-800-422-6237); TTY at 1-800-332-8615.
Source: National Institutes of Health; National Cancer Institute
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