Anal Cancer
On this page:
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).
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 or by other conditions.
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 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
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 stage of the cancer.
Where the tumor is in the anus.
The grade of the tumor.
The treatment options depend on the following:
Where the tumor is in the anus.
Whether the patient has human immunodeficiency virus (HIV).
Whether cancer remains after initial treatment or has recurred.
Return to top 
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.
The following stages are used for anal cancer:
In stage 0, cancer is found in the innermost lining of the anus only.
Stage 0 cancer is also called carcinoma in situ.
In stage I, the tumor is no larger than 2 centimeters.
In stage II, the tumor is larger than 2 centimeters.
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; 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.
In stage IV, the tumor may be any size and cancer may have spread to
lymph nodes and has spread to distant parts of the body.
Return to top
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.
Return to top
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. Before starting treatment, patients may
want to think about taking part in a clinical trial. 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.
Clinical trials are taking place in many parts of the country. Choosing the most appropriate cancer treatment is a decision that
ideally involves the patient, family, and health care team.
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.
Other types of treatment are being tested in clinical trials. These include
the following:
Radiosensitizers
Radiosensitizers are drugs that make tumor cells more sensitive to radiation
therapy. Combining radiation therapy with radiosensitizers may kill more
tumor cells.
This summary section refers to specific treatments under study in clinical
trials, but it may not mention every new treatment being studied.
Return to top
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. Before starting treatment, patients may
want to think about taking part in a clinical trial. 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.
Clinical trials are taking place in many parts of the country. Choosing the most appropriate cancer treatment is a decision that
ideally involves the patient, family, and health care team.
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.
Other types of treatment are being tested in clinical trials. These include
the following:
Radiosensitizers
Radiosensitizers are drugs that make tumor cells more sensitive to radiation
therapy. Combining radiation therapy with radiosensitizers may kill more
tumor cells.
Return to top
Stage 0 Anal Cancer (Carcinoma in Situ)
Treatment of stage 0 anal cancer 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 beam radiation.
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.
Return to top
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.
Return to top
