Anal cancer is a disease in which malignant (cancer) cells form in the tissues of the anus.

The anus is the end of the large intestine, below the rectum, through which stool (solid waste) leaves the body. The anus is formed partly from the outer skin layers of the body and partly from the intestine. Two ring-like muscles, called sphincter muscles, open and close the anal opening and let stool pass out of the body. The anal canal, the part of the anus between the rectum and the anal opening, is about 1-1 ½ inches long.

Anatomy of the lower digestive system, showing the colon and other organs.

The skin around the outside of the anus is called the perianal area. Tumors in this area are skin tumors, not anal cancer.

Being infected with the human papillomavirus (HPV) increases the risk of developing anal cancer.

Anal cancer signs and symptoms include:

• Bleeding from the anus or rectum
• Pain in the area of the anus
• A mass or growth in the anal canal
• Anal itching

When to see a doctor

Talk to your doctor about any signs and symptoms that bother you, especially if you have any factors that increase your risk of anal cancer.

Anal cancer forms when a genetic mutation turns normal, healthy cells into abnormal cells. Healthy cells grow and multiply at a set rate, eventually dying at a set time. Abnormal cells grow and multiply out of control, and they don't die. The accumulating abnormal cells form a mass (tumor). Cancer cells invade nearby tissues and can separate from an initial tumor to spread elsewhere in the body (metastasize).

Anal cancer is closely related to a sexually transmitted infection called human papillomavirus (HPV). Evidence of HPV is detected in the majority of anal cancers. HPV is thought to be the most common cause of anal cancers.

The prognosis (chance of recovery) depends on the following:

• The size of the tumor.
• Where the tumor is in the anus.
• Whether the cancer has spread to the lymph nodes.

The treatment options depend on the following:

• The stage of the cancer.
• Where the tumor is in the anus.
• Whether the patient has human immunodeficiency virus (HIV).
• Whether cancer remains after initial treatment or has recurred.

Several factors have been found to increase the risk of anal cancer, including:

• Older age. Most cases of anal cancer occur in people age 50 and older.
• Many sexual partners. People who have many sexual partners over their lifetimes have a greater risk of anal cancer.
• Anal sex. People who engage in anal sex have an increased risk of anal cancer.
• Smoking. Smoking cigarettes may increase your risk of anal cancer.
• History of cancer. Those who have had cervical, vulvar or vaginal cancer have an increased risk of anal cancer.
• Human papillomavirus (HPV). HPV infection increases your risk of several cancers, including anal cancer and cervical cancer. HPV infection is a sexually transmitted infection that can also cause genital warts.
• Drugs or conditions that suppress your immune system. People who take drugs to suppress their immune systems (immunosuppressive drugs), including people who have received organ transplants, may have an increased risk of anal cancer. HIV — the virus that causes AIDS — suppresses the immune system and increases the risk of anal cancer.

Radiation and chemotherapy are frequently combined by doctors to treat anal cancer. Together, these two therapies strengthen one another and raise the likelihood of finding a cure.

1. Chemotherapy: Chemotherapy medications can be given orally or through vein injection. Your body absorbs the chemicals, which kill quickly proliferating cells like cancer cells. Unfortunately, they also harm quickly proliferating healthy cells, such as those in your gastrointestinal tract and hair follicles. Side effects of this include nausea, vomiting, and hair loss.

2. Radiation Theory: High-powered beams, including X-rays and protons, are used in radiation therapy to kill cancer cells. A big machine moves around you as you lie on a table during radiation therapy, focusing radiation beams on certain parts of your body to target cancer.

3. Near where the beams are targeted, healthy tissue could be harmed by radiation. Redness of the skin, ulcers on and around the anus, and stiffness and narrowing of the anal canal are possible side effects.

4. Surgery to remove anal malignancies in the early stages: Surgery may be used to eliminate very tiny anal malignancies. The surgeon performs this operation to remove the tumor and a tiny patch of surrounding healthy tissue.

5. Early-stage malignancies can occasionally be removed without harming the muscles that surround the anal canal since the tumors are small. Doctors try to preserve the anal sphincter muscles since they are responsible for controlling bowel motions. After surgery, your doctor might additionally advise chemotherapy and radiation, depending on the type of cancer you have.

Symptoms
Bleeding from the anus,Anus itching
Conditions
Growth in the anal canal,Pain in the area of the anus
Drugs
Mitomycin,Fluorouracil