Anal cancer

Facts

Most people with anal cancer are cured, especially if their cancer is diagnosed early. No matter what type or stage of anal cancer you have, treatments are available.

Fred Hutchinson Cancer Center offers comprehensive anal cancer treatment from a team of experts who specialize in gastrointestinal cancers.

Gastrointestinal Refers to the stomach and intestines. Also called GI. Stage The extent of a cancer in the body. Staging is usually based on the size of the tumor, whether lymph nodes contain cancer and whether the cancer has spread from the original site to other parts of the body.

What is anal cancer?

Anal cancer occurs when cells begin to grow abnormally in:

The anus — the opening to the outside of the body at the end of the large intestine, below the rectum
The anal canal — the inch-and-a-half of tube inside the body that connects the rectum to the anus

Several layers and types of cells make up the tissues in this area. So different types of cancer can develop here, depending on which layer of cells is affected.

Whatever the type, anal cancer cells do not respond to regular cell growth, division and death signals like they are supposed to. They also don’t organize normally. Instead they grow into a tumor, which may break through surrounding layers of cells.

Types

Most anal cancers are one of these two types.

Select an option

Squamous cell carcinoma

Adenocarcinoma

Starts in thin, flat cells (squamous cells) in the skin and linings of the body. It can start in the skin around the anus (perianal skin) and in the outer lining of the anal canal. This is the most common type of anal cancer.

Starts in glands. Anal adenocarcinoma can start in cells that line the upper anal canal and in glands under the anal lining that make mucus.

Adenocarcinoma Cancer that forms in the glandular tissue that lines certain internal organs and makes and releases substances in the body, such as mucus, digestive juices or other fluids.

Cancer that forms in the glandular tissue that lines certain internal organs and makes and releases substances in the body, such as mucus, digestive juices or other fluids. Most cancers of the breast, pancreas, lung, prostate, colon, esophagus and stomach are adenocarcinomas.

Symptoms

Anal cancer may not cause any symptoms, or it may not cause symptoms until it’s advanced. Symptoms may include:

Bleeding, pain or pressure in your anal area
Itching, swelling or a lump near your anus
A change in bowel habits or diameter of your stool
Discharge from your anus that’s not normal
Swollen lymph nodes in your groin

These symptoms may be caused by conditions other than cancer. If you have any of the symptoms above, or other symptoms that concern you, see your doctor to find out the reason.

If you do have anal cancer, doctors are more likely to find it early — when it’s easier to treat — if you’re evaluated sooner rather than later.

Symptom A physical or mental problem that a person experiences that may indicate a disease or condition. Symptoms cannot be seen and do not show up on medical tests. A physical or mental problem that a person experiences that may indicate a disease or condition. Symptoms cannot be seen and do not show up on medical tests. Some examples of symptoms are headache, fatigue, nausea and pain.

Diagnosing

If you have signs or symptoms that could be from anal cancer, your doctor will start by asking about your medical history and family history and doing a physical exam. You may also need one or more of these procedures:

Digital rectal exam — Your doctor inserts a lubricated, gloved finger into your anus to feel for abnormal areas or masses.
Anoscopy — Your doctor inserts a thin, short, lighted tube called an anoscope through your anus into the lower part of your rectum to look for any abnormalities.
Flexible sigmoidoscopy — Your doctor looks at your anus and rectum using a thin, lighted tube called a sigmoidoscope.
Biopsy — During anoscopy, your doctor may remove small samples of tissue (or an entire tumor, if it’s small). A pathologist examines the cells under a microscope. This is the only way to tell whether you have anal cancer.
Imaging studies — If cancer is found, your doctor may also want you to have imaging studies, such as an X-ray, ultrasound, computed tomography (CT) scan, magnetic resonance imaging (MRI) scan or positron-emission tomography (PET) scan, to learn more about whether your cancer has spread.

Computed tomography A procedure that uses a computer linked to an X-ray machine to make a series of detailed pictures of areas inside the body. The pictures are used to create three-dimensional (3-D) views of tissues and organs. A procedure that uses a computer linked to an X-ray machine to make a series of detailed pictures of areas inside the body. The pictures are taken from different angles and are used to create three-dimensional (3-D) views of tissues and organs. A dye may be injected into a vein or swallowed to help the tissues and organs show up more clearly. This scan may be used to help diagnose disease, plan treatment or find out how well treatment is working. Imaging In medicine, a process that makes pictures of areas inside the body. Imaging uses methods such as X-rays (high-energy radiation), ultrasound (high-energy sound waves) and radio waves. Magnetic resonance imaging A procedure in which radio waves and a powerful magnet linked to a computer are used to create detailed pictures of areas inside the body. A procedure in which radio waves and a powerful magnet linked to a computer are used to create detailed pictures of areas inside the body. These pictures can show the difference between normal and diseased tissue. MRI makes better images of organs and soft tissue than other scanning techniques, such as computed tomography (CT) or X-ray. MRI is especially useful for imaging the brain, the spine, the soft tissue of joints and the inside of bones. Pathologist A physician who has special training in identifying diseases by studying cells and tissues under a microscope. Sign In medicine, a sign is something found during a physical exam or from a laboratory test that shows that a person may have a condition or disease. In medicine, a sign is something found during a physical exam or from a laboratory test that shows that a person may have a condition or disease. Some examples of signs are fever, swelling, skin rash, high blood pressure and high blood glucose. Symptom A physical or mental problem that a person experiences that may indicate a disease or condition. Symptoms cannot be seen and do not show up on medical tests. A physical or mental problem that a person experiences that may indicate a disease or condition. Symptoms cannot be seen and do not show up on medical tests. Some examples of symptoms are headache, fatigue, nausea and pain. Ultrasound A procedure that uses high-energy sound waves to look at tissues and organs inside the body. The sound waves make echoes that form pictures of the tissues and organs on a computer screen. A procedure that uses high-energy sound waves to look at tissues and organs inside the body. The sound waves make echoes that form pictures of the tissues and organs on a computer screen (sonogram). Ultrasound may be used to help diagnose diseases, such as cancer. It may also be used during pregnancy to check the fetus (unborn baby) and during medical procedures, such as biopsies. Also called ultrasonography.

Stages

The treatment that your doctors recommend for anal cancer will be based in part on the stage of your cancer. The stage depends on:

How large your cancer is
Whether the cancer has invaded nearby organs
Whether the cancer has spread to lymph nodes
Whether the cancer has spread to distant parts of your body

Anal cancers are grouped into stages I through IV, with stage I being the least advanced and stage IV being the most advanced.

Stage The extent of a cancer in the body. Staging is usually based on the size of the tumor, whether lymph nodes contain cancer and whether the cancer has spread from the original site to other parts of the body.

What causes anal cancer?

There isn't any known cause for anal cancer, but several factors may contribute to its development.

Risk factors

These factors may affect your risk for anal cancer:

Age — Most people who develop anal cancer are over age 50.
Human papillomavirus (HPV) — HPV can cause genital and anal warts (though most people with HPV don’t have warts), and some strains of the virus can cause cancer of the anus, cervix, vagina, vulva or penis. HPV is spread by skin-to-skin contact. Women who have had cervical, vaginal or vulvar cancer are more likely to get anal cancer, possibly because all these cancers can be caused by HPV. (Most people with HPV do not get cancer.)
Anal irritation — You may be at greater risk if you often have redness, swelling or soreness around your anus.
Anal fistula — A fistula is an abnormal tunnel that forms in the body. An anal fistula connects your anus to the outside of your body. Pus or liquid may drain from this tunnel.
Smoking — Smoking is linked to several types of cancer, not just lung cancer. Smokers are about eight times more likely to get anal cancer than nonsmokers.
Lowered immunity — Any condition that lowers your immune function makes it more difficult for your body to fight disease and more likely that you will develop cancer.
Human immunodeficiency virus (HIV) — Being infected with HIV, the virus that causes acquired immune deficiency syndrome (AIDS), may raise the risk for anal cancer.
Sexual activity — Having many sexual partners increases the risk for HPV, HIV and anal cancer. Also, both men and women who receive anal sex are at increased risk for anal cancer.

How common is anal cancer?

About 8,600 people are diagnosed with anal cancer in the United States each year.

Overall, women are more likely to get anal cancer than men are. African-Americans are more likely than European Americans to develop the disease. Among African-Americans, men are more likely to get this type of cancer than women are.

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