How is Anal Cancer Treated? 

Written by: Rob Levy
Medically Reviewed By: Kimberly Perez, MD

Anal cancer, which forms in tissues of the anus, the opening at the bottom of the rectum, is diagnosed in about 9,800 people each year in the United States, most often in older adults. It is more common in white women and Black men than other groups, and while it is a serious disease, it can often be treated effectively and, in many cases, cured.  

What is the treatment for anal cancer that has not spread? 

The standard treatment for anal cancer that has not spread is chemotherapy and radiation therapy. If this is not successful, surgery is used. 

Clinical trials are studying whether a combination of radiation therapy, chemotherapy, and radiosensitizers (drugs that make cancer cells more vulnerable to radiation therapy) is safe and effective this group of patients.  

How is recurrent anal cancer treated? 

Treatment may include the following: 

  • Surgery for recurrence after radiation therapy and/or chemotherapy 
  • A clinical trial of chemotherapy options 
  • A clinical trial of immune checkpoint inhibitors, which unleash an immune system attack on cancer cells 

How is metastatic anal cancer treated? 

For anal cancer that has spread, or metastasized, to other parts of the body, only chemotherapy is used, although radiation therapy may be used to relieve some of the symptoms arising from the original tumor. 

How are these treatments used? 


A wide range of chemotherapy drugs is used in the treatment of anal cancer.  Doctors weigh a variety of factors in determining which drug or combination of drugs to use in each patient. 

Radiation therapy 

External beam therapy uses a machine outside the body to send radiation toward the area of the body with cancer. The way the radiation therapy is given depends on the type and stage of the cancer being treated.  


Surgery is used only if some cancer tissue remains after treatment with chemotherapy and radiation therapy, or if the disease has recurred after these therapies.  

  • Surgeons may perform a local resection, in which the tumor and some of the healthy surrounding tissue are cut from the anus. This form of surgery may be used if the cancer is small and has not spread. It may save the sphincter muscles so the patient can still control bowel movements following surgery. Tumors that form in the lower part of the anus can often be removed with local resection. 
  • In an abdominoperineal resection, the anus, rectum, and part of the sigmoid colon (the S-shaped portion of the colon that connects to the rectum) are removed through an incision made in the abdomen. The doctor sews the end of the large intestine to an opening, called a stoma, made in the surface of the abdomen so digestive waste can be collected in a disposable bag outside of the body. This is called a colostomy. Lymph nodes that contain cancer cells may also be removed during this operation. This procedure is used only for cancer that remains or comes back after treatment with radiation therapy and chemotherapy. 
  • In a resection of the colon with colostomy, part of the colon containing the cancer and nearby healthy tissue are removed, a stoma is created, and a colostomy bag is attached to the stoma. 

What are the side effects of treatment for anal cancer? 

Each type of treatment may produce side effects in patients. Chemotherapy, for example, can lead to fatigue, hair loss, nausea, constipation, and other problems. Radiation therapy may cause fatigue and dryness, itching, blistering, or peeling of the skin in the area being treated. 

Talk with your oncologist about the types of side effects that are associated with your treatment. 

Why are follow-up tests performed after treatment? 

Some of the tests that are performed to diagnose the cancer or determine its stage – including CR scans, X-rays, Magnetic Resonance Imaging (MRI), positron emission tomography (PET), and a pelvic exam — may be repeated during or after treatment. Some of these are performed 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. 

Some tests will continue to be done from time to time after treatment has ended. The results of these tests can show if the cancer has recurred or worsened. 

How is anal cancer treated in patients with HIV? 

In general, treatment for patients who have anal cancer and the human immunodeficiency virus (HIV) is similar to treatment for other patients, and these patients have similar outcomes. However, this treatment can further damage the weakened immune systems of patients who have HIV. Treatment in patients with a historyof AIDS-related complications may require lower doses of anticancerdrugs and radiation therapy than doses used for patients who do not have HIV. 

What are some clinical trials of potential treatments for anal cancer? 

Clinical trials are evaluating a wide range of potential therapies for anal cancer. For a complete list of such trials, click here

About the Medical Reviewer

Kimberly Perez, MD