Anal cancer is a disease in which malignant (cancer) cells form in the tissues of the anus.
The anus is the end of the large intestine, below the rectum,
through which stool (solid waste) leaves the body. The anus is formed partly
from the outer, skin layers of the body and partly from the intestine. Two
ring-like muscles, called sphincter muscles, open and close the anal opening to
let stool pass out of the body. The anal canal, the part of the anus between the
rectum and the anal opening, is about 1½ inches long.
The skin around the outside of the anus is called the perianal area. Tumors in this area are skin tumors, not anal cancer.
Being infected with the human papillomavirus (HPV) can affect the risk of developing anal cancer.
Risk factors include the following:
- Being over 50 years old.
- Being infected with human papillomavirus (HPV).
- Having many sexual partners.
- Having receptive anal intercourse (anal sex).
- Frequent anal redness, swelling, and soreness.
- Having anal fistulas (abnormal openings).
- Smoking cigarettes.
Possible signs of anal cancer include bleeding from the anus or
rectum or a lump near the anus.
These and other symptoms may be caused by anal cancer. Other
conditions may cause the same symptoms. A doctor should be consulted if any of
the following problems occur:
- Bleeding from the anus or rectum.
- Pain or pressure in the area around the anus.
- Itching or discharge from the anus.
- A lump near the anus.
- A change in bowel habits.
Tests that examine the rectum and anus are used to detect (find)
and diagnose anal cancer.
The following tests and procedures may be used:
- Physical exam and history: An exam of the body to check general
signs of health, including checking for signs of disease, such as lumps or
anything else that seems unusual. A history of the patient’s health habits and
past illnesses and treatments will also be taken.
- Digital rectal examination (DRE): An exam of the anus and
rectum. The doctor or nurse inserts a lubricated, gloved finger into the lower
part of the rectum to feel for lumps or anything else that seems unusual.
- Anoscopy: An exam of the anus and lower rectum using a short,
lighted tube called an anoscope.
- Proctoscopy: An exam of the rectum using a short, lighted tube
called a proctoscope.
- Endo-anal or endorectal ultrasound: A procedure in which an
ultrasound transducer (probe) is inserted into the anus or rectum and used to
bounce high-energy sound waves (ultrasound) off internal tissues or organs and
make echoes. The echoes form a picture of body tissues called a sonogram.
- Biopsy: The removal of cells or tissues so they can be viewed
under a microscope by a pathologist to check for signs of cancer. If an abnormal
area is seen during the anoscopy, a biopsy may be done at that time.
Certain factors affect the prognosis (chance of recovery) and treatment options.
The prognosis (chance of recovery) depends on the following:
- The size of the tumor.
- Where the tumor is in the anus.
- Whether the cancer has spread to the lymph nodes.
The treatment options depend on the following:
- The stage of the cancer.
- Where the tumor is in the anus.
- Whether the patient has human immunodeficiency virus (HIV).
- Whether cancer remains after initial treatment or has recurred.
Stages of Anal Cancer
After anal cancer has been diagnosed, tests are done to find out
if cancer cells have spread within the anus or to other parts of the body.
The process used to find out if cancer has spread within the
anus or to other parts of the body is called staging. The information gathered
from the staging process determines the stage of the disease. It is important to
know the stage in order to plan treatment. The following tests may be used in
the staging process:
- CT scan (CAT scan): A procedure that makes a series of detailed
pictures of areas inside the body, taken from different angles. The pictures are
made by a computer linked to an x-ray machine. A dye may be injected into a vein
or swallowed to help the organs or tissues show up more clearly. This procedure
is also called computed tomography, computerized tomography, or computerized
axial tomography. For anal cancer, a CT scan of the pelvis and abdomen may be
done.
- Chest x-ray: An x-ray of the organs and bones inside the chest.
An x-ray is a type of energy beam that can go through the body and onto film,
making a picture of areas inside the body.
- Endo-anal or endorectal ultrasound: A procedure in which an
ultrasound transducer (probe) is inserted into the anus or rectum and used to
bounce high-energy sound waves (ultrasound) off internal tissues or organs and
make echoes. The echoes form a picture of body tissues called a sonogram.
There are three ways that cancer spreads in the body.
The three ways that cancer spreads in the body are:
- Through tissue. Cancer invades the surrounding normal tissue.
- Through the lymph system. Cancer invades the lymph system and
travels through the lymph vessels to other places in the body.
- Through the blood. Cancer invades the veins and capillaries and
travels through the blood to other places in the body.
When cancer cells break away from the primary (original) tumor
and travel through the lymph or blood to other places in the body, another
(secondary) tumor may form. This process is called metastasis. The secondary
(metastatic) tumor is the same type of cancer as the primary tumor. For example,
if breast cancer spreads to the bones, the cancer cells in the bones are
actually breast cancer cells. The disease is metastatic breast cancer, not bone cancer.
The following stages are used for anal cancer:
Stage 0 (Carcinoma in Situ)
In stage 0, abnormal cells are found in the innermost lining of
the anus. These abnormal cells may become cancer and spread into nearby normal
tissue. Stage 0 is also called carcinoma in situ.
Stage I
In stage I, cancer has formed and the tumor is 2 centimeters or smaller.
Stage II
In stage II, the tumor is larger than 2 centimeters.
Stage IIIA
In stage IIIA, the tumor may be any size and has spread to either:
- lymph nodes near the rectum; or
- nearby organs, such as the vagina, urethra, and bladder.
Stage IIIB
In stage IIIB, the tumor may be any size and has spread:
- to nearby organs and to lymph nodes near the rectum; or
- to lymph nodes on one side of the pelvis and/or groin, and may
have spread to nearby organs; or
- to lymph nodes near the rectum and in the groin, and/or to lymph
nodes on both sides of the pelvis and/or groin, and may have spread to nearby organs.
Stage IV
In stage IV, the tumor may be any size and cancer may have
spread to lymph nodes or nearby organs and has spread to distant parts of the body.
Recurrent Anal Cancer
Recurrent anal cancer is cancer that has recurred (come back)
after it has been treated. The cancer may come back in the anus or in other
parts of the body.
Treatment Option Overview
There are different types of treatment for patients with anal cancer.
Different types of treatments are available for patients with
anal cancer. Some treatments are standard (the currently used treatment), and
some are being tested in clinical trials. A treatment clinical trial is a
research study meant to help improve current treatments or obtain information on
new treatments for patients with cancer. When clinical trials show that a new
treatment is better than the standard treatment, the new treatment may become
the standard treatment. Patients may want to think about taking part in a
clinical trial. Some clinical trials are open only to patients who have not
started treatment.
Three types of standard treatment are used:
Radiation therapy
Radiation therapy is a cancer treatment that uses high-energy
x-rays or other types of radiation to kill cancer cells. There are two types of
radiation therapy. External radiation therapy uses a machine outside the body to
send radiation toward the cancer. Internal radiation therapy uses a radioactive
substance sealed in needles, seeds, wires, or catheters that are placed directly
into or near the cancer. The way the radiation therapy is given depends on the
type and stage of the cancer being treated.
Chemotherapy
Chemotherapy is a cancer treatment that uses drugs to stop the
growth of cancer cells, either by killing the cells or by stopping the cells
from dividing. When chemotherapy is taken by mouth or injected into a vein or
muscle, the drugs enter the bloodstream and can reach cancer cells throughout
the body (systemic chemotherapy). When chemotherapy is placed directly into the
spinal column, an organ, or a body cavity such as the abdomen, the drugs mainly
affect cancer cells in those areas (regional chemotherapy). The way the
chemotherapy is given depends on the type and stage of the cancer being treated.
Surgery
- Local resection: A surgical procedure in which the tumor is cut
from the anus along with some of the healthy tissue around it. Local resection
may be used if the cancer is small and has not spread. This procedure may save
the sphincter muscles so the patient can still control bowel movements. Tumors
that develop in the lower part of the anus can often be removed with local
resection.
- Abdominoperineal resection: A surgical procedure in which the
anus, the rectum, and part of the sigmoid colon are removed through an incision
made in the abdomen. The doctor sews the end of the intestine to an opening,
called a stoma, made in the surface of the abdomen so body waste can be
collected in a disposable bag outside of the body. This is called a colostomy.
Lymph nodes that contain cancer may also be removed during this operation.
Having the human immunodeficiency virus can affect
treatment of anal cancer.
Cancer therapy can further damage the already weakened immune
systems of patients who have the human immunodeficiency virus (HIV). For this
reason, patients who have anal cancer and HIV are usually treated with lower
doses of anticancer drugs and radiation than patients who do not have HIV.
New types of treatment are being tested in clinical trials.
This section describes treatments that are being studied
in clinical trials. It may not mention every new treatment being studied.
Information about clinical trials is available from the NCI Web site.
Radiosensitizers
Radiosensitizers are drugs that make tumor cells more sensitive
to radiation therapy. Combining radiation therapy with radiosensitizers may kill
more tumor cells.
Patients may want to think about taking part in a clinical trial.
For some patients, taking part in a clinical trial may be the
best treatment choice. Clinical trials are part of the cancer research process.
Clinical trials are done to find out if new cancer treatments are safe and
effective or better than the standard treatment.
Many of today's standard treatments for cancer are based on
earlier clinical trials. Patients who take part in a clinical trial may receive
the standard treatment or be among the first to receive a new treatment.
Patients who take part in clinical trials also help improve the
way cancer will be treated in the future. Even when clinical trials do not lead
to effective new treatments, they often answer important questions and help move
research forward.
Patients can enter clinical trials before, during, or after starting their cancer treatment.
Some clinical trials only include patients who have not yet
received treatment. Other trials test treatments for patients whose cancer has
not gotten better. There are also clinical trials that test new ways to stop
cancer from recurring (coming back) or reduce the side effects of cancer treatment.
Follow-up tests may be needed.
Some of the tests that were done to diagnose the cancer or to
find out the stage of the cancer may be repeated. Some tests will be repeated in
order to see how well the treatment is working. Decisions about whether to
continue, change, or stop treatment may be based on the results of these tests.
This is sometimes called re-staging.
Some of the tests will continue to be done from time to time
after treatment has ended. The results of these tests can show if your condition
has changed or if the cancer has recurred (come back). These tests are sometimes
called follow-up tests or check-ups.
Treatment Options by Stage
For some types or stages of cancer, there may not be any
trials listed. Check with your doctor for clinical trials that are not listed
here but may be right for you.
Stage 0 (Carcinoma in Situ)
Treatment of stage 0 is usually local resection.
Stage I Anal Cancer
Treatment of stage I anal cancer may include the following:
- Local resection.
- External-beam radiation therapy with or without chemotherapy. If
cancer remains after treatment, additional chemotherapy and radiation therapy
may be given to avoid the need for a permanent colostomy.
- Internal radiation therapy.
- Abdominoperineal resection, if cancer remains or comes back
after treatment with radiation therapy and chemotherapy.
- Internal radiation therapy for cancer that remains after
treatment with external-beam radiation therapy.
Patients who have had treatment that saves the sphincter muscles
may receive follow-up exams every 3 months for the first 2 years, including
rectal exams with endoscopy and biopsy, as needed.
Stage II Anal Cancer
Treatment of stage II anal cancer may include the following:
- Local resection.
- External-beam radiation therapy with chemotherapy. If cancer
remains after treatment, additional chemotherapy and radiation therapy may be
given to avoid the need for a permanent colostomy.
- Internal radiation therapy.
- Abdominoperineal resection, if cancer remains or comes back
after treatment with radiation therapy and chemotherapy.
- A clinical trial of new treatment options.
Patients who have had treatment that saves the sphincter muscles
may receive follow-up exams every 3 months for the first 2 years, including
rectal exams with endoscopy and biopsy, as needed.
Stage IIIA Anal Cancer
Treatment of stage IIIA anal cancer may include the following:
- External-beam radiation therapy with chemotherapy. If cancer
remains after treatment, additional chemotherapy and radiation therapy may be
given to avoid the need for a permanent colostomy.
- Internal radiation therapy.
- Abdominoperineal resection, if cancer remains or comes back
after treatment with chemotherapy and radiation therapy.
- A clinical trial of new treatment options.
Stage IIIB Anal Cancer
Treatment of stage IIIB anal cancer may include the following:
- External-beam radiation therapy with chemotherapy.
- Local resection or abdominoperineal resection, if cancer remains
or comes back after treatment with chemotherapy and radiation therapy. Lymph
nodes may also be removed.
- A clinical trial of new treatment options.
Stage IV Anal Cancer
Treatment of stage IV anal cancer may include the following:
- Surgery as palliative therapy to relieve symptoms and improve
the quality of life.
- Radiation therapy as palliative therapy.
- Chemotherapy with radiation therapy as palliative therapy.
- A clinical trial of new treatment options.
Treatment Options for Recurrent Anal Cancer
Treatment of recurrent anal cancer may include the following:
- Radiation therapy and chemotherapy, for recurrence after surgery.
- Surgery, for recurrence after radiation therapy and/or chemotherapy.
- A clinical trial of radiation therapy with chemotherapy and/or radiosensitizers.
Check for U.S. clinical trials from NCI's PDQ Cancer Clinical
Trials Registry that are now accepting patients with recurrent anal cancer. For
more specific results, refine the search by using other search features, such as
the location of the trial, the type of treatment, or the name of the drug.
General information about clinical trials is available from the NCI Web site.
More Information
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
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. Information about ongoing clinical trials is available from the NCI Web site www.cancer.gov/clinicaltrials
Source: National Institutes of Health; National Cancer Institute
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This information is provided by the Cleveland Clinic and is not intended to replace the medical advice of your doctor or health care provider. Please consult your health care provider for advice about a specific medical condition. This document was last reviewed on 6/13/2008...#6151
