Anal Cancer

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Treating Anal Cancer TOPICS

Treatment of anal cancer, by stage

The type of treatment your cancer care team will recommend depends on the type of anal cancer, where it is, and how far it has spread. This section sums up the options for anal cancer treatment according to the stage (extent) of disease.

Anal tumors affecting the anal margin or the perianal skin (and not the anal canal) are sometimes treated differently from anal canal cancers.

Stage 0

At this stage, the cancer is still only in the inner lining of the anus and has not grown into deeper layers. Anal cancers are not usually found at this early stage.

Stage 0 tumors can often be removed completely by surgery (local resection). Radiation therapy and chemotherapy (chemo) are rarely needed.

Stages I and II

These cancers have grown into the anal wall but have not yet grown into nearby organs or spread to the lymph nodes.

Surgery (local resection) can be used to remove some small tumors (usually less than 1 centimeter or ½ inch) that do not involve the sphincter. In some cases, this may be followed with chemo and radiation therapy.

The standard treatment for anal cancers that can’t be removed without harming the anal sphincter is radiation therapy combined with chemo (chemoradiation). In chemoradiation, the 2 treatments are given over the same time period. The chemo usually consists of 5-FU with mitomycin C. The mitomycin is given as a short intravenous (IV) injection, usually at the start of radiation treatment and then again near the end, at around 4 to 6 weeks. The 5-FU is often given by a long IV infusion over 4 to 5 days and repeated in 4 to 6 weeks. In some cases, your doctor may suggest internal radiation along with the external beam radiation.

If the cancer hasn’t gone away completely after the chemoradiation has been completed, more treatment might be needed. But it is important to know that it may still take several months to see the full effects of treatment on the cancer. Doctors may watch any remaining cancer for up to 6 months, as it may continue to shrink and even go away without further treatment.

If further treatment is needed, sometimes additional chemo (with or without extra radiation) may be given to try to shrink any remaining cancer. The drugs most often used are 5-FU plus cisplatin. Another option would be surgery to remove the remaining cancer. This is most often an extensive operation known as an abdominoperineal resection (APR), but sometimes only a local resection might be needed (see “Surgery for anal cancer”).

Stages IIIA and IIIB

These cancers have grown into nearby organs or reached nearby lymph nodes, but they have not spread to distant parts of the body.

In most cases, the first treatment will be radiation therapy combined with chemo (chemoradiation). In chemoradiation, both treatments are given over the same time period. The chemo usually consists of 5-FU with mitomycin C. The mitomycin is given as a short intravenous (IV) injection, usually at the start of radiation treatment and then again near the end, at around 4 to 6 weeks. The 5-FU is often given by a long IV infusion over 4 to 5 days and repeated in 4 to 6 weeks. In some cases, your doctor may suggest internal radiation along with the external beam radiation.

If some cancer remains after the chemoradiation, it may be watched closely for up to 6 months because it could still take several months to see the full effects of treatment on the cancer. If the cancer gets larger, more treatment is needed. Some patients are given more chemo. The drugs most often used are 5-FU plus cisplatin. Sometimes more radiation is given as well (this is called a radiation boost). Another option is to remove the cancer with surgery. This is most often an extensive operation known as an abdominoperineal resection (APR), but sometimes only a local resection is needed. If the cancer has spread to local lymph nodes, these may be removed with surgery or treated with radiation therapy.

Stage IIIB anal cancer can be hard to treat, so patients with this stage might be helped by taking part in a clinical trial.

Stage IV

In this stage, the cancer has spread to distant organs or tissues. Most often, anal cancer first spreads to the lungs, liver, brain, or bones, but it can spread anywhere.

Treatment is very unlikely to cure these cancers. Treatment is aimed at controlling the disease for as long as possible and relieving symptoms as much as possible. Chemotherapy, sometimes along with radiation, is usually the standard treatment. The drugs most often used are 5-FU and cisplatin. Surgery might also be an option in some cases, but before having any surgery it’s important that you understand its goal (to prolong life, relieve symptoms, etc.) and the possible risks and side effects.

Because these cancers can be hard to treat, people might also want to think about taking part in a clinical trial of newer treatments.

Anal melanoma

Melanoma doesn’t respond well to chemotherapy or radiation, so surgery to remove the cancer is the main treatment when possible. Early stage anal melanomas are treated with surgery to remove the tumor and a rim of surrounding normal tissue (local excision). If the tumor is large or has grown into deeper tissues (such as the sphincter muscle) a bigger operation, such as an abdominoperineal resection (APR) may be needed.

If the melanoma has spread to other organs, it is treated like skin melanoma that has spread, often with immunotherapy or targeted therapy drugs. For more information about the treatment of advanced melanoma, see our document Melanoma Skin Cancer.

Recurrent anal cancer

Cancer is called recurrent when it comes back after treatment. Recurrence can be local (in or near the same place it started) or distant (spread to organs such as the lungs or bone).

If cancer returns in the anus or nearby lymph nodes after treatment, treatment depends on what treatment you had the first time. For example, if you had surgery alone, you may receive radiation therapy and chemo (chemoradiation). If you first had chemoradiation, then you can be treated with surgery and/or chemo. Treating recurrent anal cancer often requires an abdominoperineal resection (APR).

In some people, the cancer will come back in distant sites or organs in the body. The most common sites are the liver and lungs. The main treatment for this is usually chemo. The typical chemo drugs used are 5-FU and cisplatin. Chemo might not cure the cancer, but it can often help control it and reduce any symptoms it is causing. In rare cases surgery or radiation therapy might be options to help treat these cancers. But as with chemo, they are unlikely to cure these cancers, so be sure you understand the goal of these treatments if they are offered.

Clinical trials of newer treatments might also be useful for people with recurrent anal cancer.

HIV-infected patients

Most people with HIV infection can be given the same treatment as others with anal cancer, and they can have a good outcome. Patients who have advanced HIV disease and weakened immune systems may need to have less intensive chemotherapy.


Last Medical Review: 04/09/2014
Last Revised: 05/02/2014