Anal Cancer

What Is Anal Cancer?

Overview: Anal Cancer

What Is Anal Cancer?

Anal cancer begins in the end of the large intestine (colon), called the anus. The anus is about an inch and a half long and connects the lower part of the large intestine to the outside of the body. The anus opens to allow the passage of stool (feces) during a bowel movement. It is lined with cells that are like the cells lining the bladder, vagina, urethra, and other places in the body. These cells are known as squamous cells.

Many kinds of tumors can grow in the anus. Some can start off harmless but later change into cancer. These tumors are referred to as potentially pre-cancerous. The term "dysplasia" (dis-play-zhuh) is also used to describe this condition. Other tumors of the anus are not cancerous, and are called "benign" (be-nine). Examples of benign tumors are warts and skin tags (small pieces of skin that hang loose from the body).


Types of Cancerous Anal Tumors

Squamous cell carcinomas are the most common type of anal cancer. These tumors begin in the cells that line the lower part of the anus and most of the anal canal. In its earliest stages it is known as carcinoma in situ (in-SY-too) or CIS. It may also be called Bowen disease. In CIS, the cancer is only in the surface cells and has not spread to any other tissue. If the cancer has spread beyond the surface cells it is called invasive.

Cloacogenic (clo-ah-kuh-jen-ik) carcinomas: This is a type of squamous cell cancer that starts in an area of the anus called the cloaca (clo-a-kuh).

Adenocarcinomas (add-uh-no car-suh-no-muh): A small number of anal cancers start in the glands found in the anal area. These cancers are known as adenocarcinomas. Paget disease is a type of adenocarcinoma that spreads through the surface layer of skin and can occur in the anal area. This should not be confused with Paget disease of the bone which is a very different disease.

Most adenocarcinomas start in the rectum and are treated as rectal carcinomas. For more information on this see the American Cancer Society document, Colorectal Cancer.

Skin Cancers: A small percentage of anal cancers are basal cell carcinomas, a type of skin cancer. Another 1%-2% are melanomas, another type of skin cancer. Melanomas are far more common on parts of the body that are exposed to the sun. Unfortunately, most anal melanomas are found at a late stage because they are hard to see.

What Causes Anal Cancer?

A risk factor is anything that increases a person's chance of getting a disease. Although the exact cause of anal cancer is not known, most anal cancers seem to be linked to infection with HPV (human papilloma virus). Still, most people with HPV infections do not get anal cancer. The risk factors for anal cancer are listed below. But having a risk factor, or even several, does not mean that you will get the disease.

Risk Factors for Anal Cancer

HPV (human papilloma virus)

Most doctors think that squamous cell anal cancer is caused by a type of this virus called HPV-16. The virus spreads during sex. It is more likely to be found in people who have had many sex partners. One sign of infection with this virus is genital warts, but most people infected with HPV do not have genital warts.

Sex

Having many sex partners is a risk factor for women. Having anal sex is a risk factor for both men and women, especially under the age of 30.

Smoking

Harmful chemicals from smoke get into the bloodstream and increase the risk of anal cancer in smokers. Current smokers are several times more likely to have cancer of the anus compared with people who never smoked. Quitting smoking reduces this risk. People who used to smoke but have quit are only slightly more likely to get this cancer compared with people who never smoked.

Lowered immunity / HIV infection

People with weakened immune systems are at higher risk for anal cancer. This includes people who have had transplants (who must take drugs to suppress their immune systems) and people with HIV infection (human immunodeficiency virus or the virus that causes AIDS).

How Is Anal Cancer Found?

Many cases of anal cancer can be found early. Anal cancers form in a part of the body that the doctor can see and reach easily. Sometimes anal cancer does not cause any symptoms at all. A rectal exam will find some cases early. For this exam, the doctor inserts a gloved finger into the anus to feel for lumps or growths. The American Cancer Society suggests that all men over the age of 50 be offered a rectal exam every year to check for prostate cancer. For women, the rectal exam is done as part of the pelvic exam. If you are concerned about anal cancer, ask your doctor if you should have the exam more often - or other tests as well.

Recently, doctors have tested people at high risk for sexually transmitted diseases with a test called an anal Pap. It is much like the Pap smear done for cervical cancer. The anal lining is swabbed and the cells are looked at under a microscope. Some doctors think that this test should be done routinely for people at high risk for anal cancer. That would include men who have sex with men, women who have had cervical cancer or vulvar cancer, all HIV-positive men and women, and all transplant patients. People with positive results should be referred for a biopsy and, depending on the results, treated.

Symptoms of Anal Cancer

People who have symptoms of anal cancer may notice one or more of the following:

• bleeding or itching around the anus
• pain in the anal area
• change in the width of the stool, stool may be narrower than usual
• swollen lymph nodes in the anal or groin area
• abnormal discharge from the anus

These symptoms can also be caused by something other than cancer, but only your doctor can tell for sure. Talk to your doctor right away if you notice any of these problems.

Tests for Anal Cancer

If your doctor has any reason to suspect anal cancer, you will need to have some more tests. Most of these tests allow the doctor to look inside the anus. Your doctor can explain the details of any other tests to be done.

Biopsy

If a suspicious growth is found, your doctor will want to do a biopsy. For this, a small piece of the growth is cut out and sent to a lab to be looked at under a microscope. If the tumor is very small and has not grown below the surface of the anus, your doctor may try to remove the entire tumor during the biopsy.

Since anal cancer can spread through the lymph system, your doctor may want to do a biopsy of your lymph nodes, too. Lymph nodes are bean-sized collections of immune system cells. Swollen lymph nodes are sometimes a sign of spreading cancer. Most often, though, they are a sign of infection. A small needle is placed into the swollen node. It is used to remove some cells and fluid that is then sent to the lab. In some cases, an operation to remove the lymph nodes near the anus may be done.

Sentinel Node Biopsy

There is a new test called the sentinel node biopsy. In this method, a radioactive substance, often with a blue dye, is injected around the tumor. If there has been spread of the cancer to the lymph nodes, the dye will go into those nodes. The surgeon then takes out any blue-stained nodes and looks at them to see if they contain cancer cells. While this test has been shown to be useful for some other cancers, it's not yet clear how helpful it is for anal cancer.

Tests to Find out how Much Cancer There Is and Where It Is

If you have cancer, other tests such as the ones below can help to find the extent of the cancer and whether it has spread.

Ultrasound

Ultrasound uses sound waves to make a picture of the inside of the body. Most people know about ultrasound because it is often used to look at a baby during pregnancy. For anal cancer, a probe must be placed in the rectum, which can be slightly uncomfortable but not painful. This test can show how far the cancer might have grown into nearby tissues.

CT Scan (Computed Tomography or CAT Scan)

A CT scan machine moves around you and uses x-rays to take many pictures of the body. A computer puts these pictures together to make pictures of cross-sections of the body. CT scans take longer than regular x-rays and you need to lie still on a table for 15 to 30 minutes. You might also feel a bit confined by the machine you lie in while the pictures are taken. But CT scans are getting faster all the time.

You may need an IV line through which the contrast "dye" is injected. The injection can sometimes cause flushing. Some people are allergic and get hives or rarely more serious reactions, such as trouble breathing and low blood pressure. Be sure to tell the doctor if you have ever had a reaction to any contrast material used for x-rays. You may also be asked to drink 1 to 2 pints of a contrast solution. This helps outline the intestine so that it is not mistaken for tumors.

A CT scan can help tell whether anal cancer has spread to the liver or other organs.

MRI (Magnetic Resonance Imaging)

Like CT scans, MRI scans show a cross-section of the body but in more detail. MRI uses radio waves and strong magnets instead of x-rays. They take longer and you have to lie inside a tube-like machine, which can be upsetting for some people. Newer, "open" MRI machines are sometimes available. MRI machines also make loud thumping noises that can be distracting. Some places offer earplugs or headphones playing music to help reduce the noise of the machine. MRI scans are very helpful in looking at the brain and spinal cord.

Chest X-rays

These may be done to see whether the anal cancer has spread to the lungs.

PET Scan (Positron Emission Tomography)

This test involves the injection of sugar combined with a radioactive atom. Cancer cells absorb high amounts of the sugar and a special camera is used to see the results. PET scans look for cancer in the whole body. They are useful when the doctor thinks the cancer has spread but doesn't know where.

How Is Anal Cancer Treated?

This information represents the views of the doctors and nurses serving on the American Cancer Society's Cancer Information Database Editorial Board. These views are based on their interpretation of studies published in medical journals, as well as their own professional experience.

The treatment information in this document is not official policy of the Society and is not intended as medical advice to replace the expertise and judgment of your cancer care team. It is intended to help you and your family make informed decisions, together with your doctor.

Your doctor may have reasons for suggesting a treatment plan different from these general treatment options. Don't hesitate to ask him or her questions about your treatment options.

There is treatment for every type and stage of anal cancer. The exact treatment you receive depends on many factors. The location, type, and stage of the tumor are very important. Your age, health, and personal wishes must also be considered.

There are 3 main types of treatment for anal cancer: surgery, radiation, and chemotherapy. Often the best approach uses 2 or more of these. In the past, surgery was the only treatment, but doctors have found that most anal cancers can be successfully treated with radiation and chemotherapy combined, without the need for surgery. This treatment approach, called chemoradiotherapy, is now the most widely used approach.

The goal of treatment may be to cure the cancer. If that is not possible, the goal may be to prevent the tumor from spreading or to keep it from coming back for as long as possible. Another goal may be to relieve symptoms such as pain or bleeding. An important part of the plan is to try to treat the cancer without affecting your ability to control your bowel movements.

Surgery

Surgery is no longer the standard option for most people with anal cancer. In people who do need surgery, the type of operation depends on the type and place of the tumor.

Local Resection

A local resection may be done if the cancer has not spread to nearby tissues or lymph nodes. In this operation, only the tumor and a small area of tissue around the tumor are removed. In most cases the muscle that opens and closes the anus (called the sphincter muscle) is saved. If so, you will be able to have bowel movements as usual afterwards.

Abdominoperineal Resection (APR)

A more involved approach is used for cancer that has spread. It is called an abdominoperineal (ab-dom-uh-no per-uh-nee-uhl) resection or APR. For this surgery, the surgeon makes a cut through the abdomen and in the area between the anus and the sexual organs. Then the anus and part of the rectum are removed. An APR is usually used only if other treatments do not work..

After an APR you will need to have a new opening made in your lower abdomen to pass stool. This opening is called a colostomy (kuh-lah-stuh-me). Stool passes through this opening into a bag attached outside the body. If you would like to know more about colostomies, see Colostomy: A Guide. This surgery can often be avoided by using radiation and chemotherapy to treat the cancer.

Radiation Therapy

Radiation therapy is treatment with high energy rays (such as x-rays) to kill or shrink cancer cells. The radiation may be given from outside the body (external radiation) or from radioactive materials placed directly in the tumor (internal or implant radiation). Sometimes doctors give radiation to shrink a tumor so it is easier to remove during surgery.

External radiation

This type of treatment is often given 5 days a week for about 5 weeks. It is much like getting a normal x-ray. But there can be side effects from this treatment. The skin of the place that is treated may look sunburned. There might also be some short-term discomfort when having bowel movements. Side effects of radiation therapy vary depending on the area of the body that is treated. Other possible side effects include feeling very tired (fatigue), upset stomach (nausea), or diarrhea when the anal area is irradiated. Also, women have a higher risk of having fractures of the pelvis or hip when they are older, even years after they had the radiation therapy.

Internal Radiation

This kind of radiation treatment involves minor surgery to put the radioactive seeds or pellets inside the body, in or near the tumor. This is called internal radiation or brachytherapy (brake-ee-THER-uh-pee). The radioactive pellets slowly release their dose over a period of time. Though the pellets stop being radioactive after a while, they stay in place for the rest of your life. Fewer trips to the doctor are needed with this treatment. This approach is used less often than external radiation. When it is used, it is usually given along with external radiation. The possible side effects are often like those seen with external radiation.

Chemotherapy

Chemotherapy or chemo is the use of drugs for treating cancer. The drugs can be swallowed in pill or liquid form or they can be injected through a needle into a vein or muscle. Once the drugs enter the bloodstream, they spread through the whole body to reach and destroy the cancer cells.

Often 2 or more drugs are used together because one drug can boost the power of the other. In anal cancer, chemo combined with radiation therapy often cures the cancer without the need for surgery. Or the doctor might use chemo after surgery to destroy any remaining cancer cells.

While chemo drugs kill cancer cells, they also damage some normal cells, causing side effects. These side effects will depend on the type of drug, how much you get, and how long you take it. Common side effects may include:

• nausea and vomiting
• loss of appetite
• diarrhea
• mouth sores
• hair loss
• easy bruising (from a shortage of blood platelets)
• feeling very tired (fatigue) or short of breath (from a shortage of red blood cells)
• increased chance of infection (from a shortage of white blood cells).

Most of the side effects go away when treatment is over. Talk with your doctor or nurse about side effects, as there are often ways to help.

Anal Cancer Survival

Because anal cancer is not common, survival rates are not exact. While these numbers give an overall picture, keep in mind that every person is different. Statistics can�t predict what will happen in your case. Talk with your cancer care team if you have questions about your own chances of a cure, or how long you might survive your cancer. They know your situation best.

The numbers below are from the SEER database of the National Cancer Institute. The SEER system groups anal cancer into 3 groups: localized (roughly stages I and II); regional (roughly stage IIIA); and distant (roughly stages IIIB and IV).

Extent	5-Year Survival Rate
Localized	82%
Regional	60%
Distant	19%

The overall relative survival rate is around 61% for men and 73% for women. The 5-year survival rate refers to the percentage of patients who are alive at least 5 years after diagnosis (leaving out those who die of other causes). Of course, patients might live much more than 5 years after their cancer is found.