What is anal cancer?

Cancer starts when cells change (mutate) and grow out of control. The changed (abnormal) cells often grow to form a lump or mass called a tumor. Cancer cells can also grow into (invade) nearby areas. And they can spread to other parts of the body. This is called metastasis.

The anus is the last part of the digestive tract. It's the opening where stool comes out of the body. It’s a short tube made of layers of tissue and rings of muscles (called sphincter muscles). You control these muscles during a bowel movement so stool can pass through.

Most anal cancers start in the cells that form the inside lining of the anus. This cancer is called squamous cell carcinoma . From the lining, it can spread deeper into the other layers of the anus and the sphincter muscles.

Who is at risk for anal cancer?

A risk factor is anything that may increase your chance of having a disease. The exact cause of someone’s cancer may not be known. But risk factors can make it more likely for a person to have cancer. Some risk factors may not be in your control. But others may be things you can change. 

The risk factors for anal cancer include:

• HPV (human papillomavirus) infection

• Many sex partners, which increases the risk of HPV and HIV infection

• Anal sex

• A weakened immune system because of HIV or other causes

• Smoking

• Older age

• Frequent inflammation in the anal area

• History of anal fistulas

Talk with your healthcare provider about your risk factors for anal cancer and what you can do about them.

Can anal cancer be prevented?

There’s no sure way to prevent anal cancer. But there are some things that may help lower your risk for it, such as: 

• Get the HPV vaccine before you start having sex.

• Don’t have anal sex.

• Limit your number of sex partners.

• Use condoms every time you have any type of sex (vaginal, anal, or oral).

• Treat HIV.

• Don’t smoke. Ask your healthcare provider for help quitting if needed.

What are the symptoms of anal cancer?

Sometimes anal cancer doesn’t cause symptoms until it grows or spreads. Some common symptoms of anal cancer are:

• Bleeding from the anus

• Pain or pressure around your anus

• Itching around your anus

• Fluid leaking from your anus

• Narrower stools or other changes in your bowel movements

• A lump or swelling near your anus

• Swollen lymph nodes in your anal or groin area

Many of these may be caused by other health problems. Still, it’s important to see a healthcare provider if you have these symptoms. Only a healthcare provider can tell if you have cancer.

How is anal cancer diagnosed?

Your healthcare provider will ask you about your health history, symptoms, risk factors, and family history of disease. A physical exam will be done. This may include a digital rectal exam (DRE). During a DRE, your provider puts a gloved, lubricated finger into your rectum to check for lumps or other changes in your anus and rectum. 

You may have blood tests done and one or more of these tests:

• Anoscopy

• Proctoscopy

• Ultrasound

• Colonoscopy

A biopsy is the only sure way to tell for sure if you have anal cancer. Small pieces of tissue are taken out from the tumor and tested for cancer cells. Your results will come back in about one week.

After a diagnosis of anal cancer, you’ll need more tests. These help your healthcare providers learn more about your overall health and the cancer. They're used to find out the stage of the cancer. The stage is how much cancer there is and how far it has spread (metastasized) in your body. It's one of the most important things to know when deciding how to treat the cancer.

Once your cancer is staged, your healthcare provider will talk with you about what this means for your treatment. Be sure to ask your healthcare provider to explain the details of your cancer to you in a way you can understand.

How is anal cancer treated?

Your treatment choices depend on the type of anal cancer you have, test results, and the stage of the cancer. Other things to think about are if the cancer can be removed with surgery, how stool will come out of your body after treatment, and your overall health. The goal of treatment may be to cure you, control the cancer, or help ease problems caused by the cancer. Talk with your healthcare team about your treatment choices, the goals of treatment, and what the risks and side effects may be.

Types of treatment for cancer are either local or systemic. Local treatments remove, destroy, or control cancer cells in one area. Surgery and radiation are local treatments. Systemic treatment is used to destroy or control cancer cells that may have traveled around your body. When taken by pill or injection, chemotherapy is a systemic treatment. You may have just one treatment or a combination of treatments.

Anal cancer can be treated with:

• Radiation therapy

• Chemotherapy

• Surgery

Talk with your healthcare providers about your treatment options. Make a list of questions. Ask about the benefits and possible side effects of each option. Talk about your concerns with your healthcare provider before making a decision.

What are treatment side effects? 

Cancer treatment, such as chemotherapy and radiation, can damage normal cells. This can cause side effects, like hair loss, mouth sores, and vomiting. Talk with your healthcare provider about side effects linked to your treatment. There are often ways to manage them. There may be things you can do and medicines you can take to help prevent or control many treatment side effects.

Depending on where the tumor is and how big it is, a lot of tissue may need to be removed with surgery. If the anus and rectum are removed, you’ll no longer be able to pass stool the same way. The surgeon will make an opening on your belly that's attached to your large intestine. This is called a colostomy. A plastic bag sticks to the skin around the opening (or stoma) to collect the stool as it comes out. If you need surgery for anal cancer, be sure to talk with your healthcare provider about what you can expect.

Coping with anal cancer

Many people feel worried, depressed, and stressed when dealing with cancer. Getting treatment for cancer can be hard on your mind and body. Keep talking with your healthcare team about any problems or concerns you may have. Work together to ease the effect of cancer and its symptoms on your daily life.

Here are tips:

• Talk with your family or friends.

• Ask your healthcare team or social worker for help.

• Speak with a counselor.

• Talk with a spiritual advisor, such as a minister or rabbi.

• Ask your healthcare team about medicines for depression or anxiety.

• Keep socially active.

• Join a cancer support group.

Cancer treatment is also hard on the body. To help yourself stay healthier, try to:

• Eat a healthy diet, with a focus on high-protein foods.

• Drink plenty of water, fruit juices, and other liquids.

• Keep physically active.

• Rest as much as needed.

• Talk with your healthcare team about ways to manage treatment side effects.

• Take your medicines as directed by your team.

When should I call my healthcare provider?

Your healthcare provider will talk with you about when to call. You may be told to call if you have:

• New symptoms or symptoms that get worse

• Signs of an infection, such as a fever

• Side effects of treatment that affect your daily function or don’t get better with treatment

Ask your healthcare provider what signs to watch for and when to call. Know how to get help after office hours and on weekends and holidays.

Next steps

Tips to help you get the most from a visit to your healthcare provider:

• Know the reason for your visit and what you want to happen.

• Before your visit, write down questions you want answered.

• Bring someone with you to help you ask questions and remember what your provider tells you.

• At the visit, write down the name of a new diagnosis and any new medicines, treatments, or tests. Also write down any new instructions your provider gives you.

• Know why a new medicine or treatment is prescribed, and how it will help you. Also know what the side effects are.

• Ask if your condition can be treated in other ways.

• Know why a test or procedure is recommended and what the results could mean.

• Know what to expect if you do not take the medicine or have the test or procedure.

• If you have a follow-up appointment, write down the date, time, and purpose for that visit.

• Know how you can contact your healthcare provider if you have questions.