According to the American Cancer Society, more than 5,000 people are diagnosed with anal cancer in the United States each year. Unfortunately, this figure is increasing. The average age of people diagnosed with anal cancer is the early 60s. It occurs slightly more often in women than men because more women have human papilloma virus (HPV), which is a risk factor for anal cancer. Anal cancer often can be treated successfully if it is found early.
The anus, which is about 1-1/2 inches long, connects the rectum (lower part of the large intestine) to the outside of the body. It allows solid waste (also called stool or feces) to pass from the body. The sphincter is two muscles that open and close the anus to let waste pass. The anus is lined with squamous cells, which also are found in the bladder, cervix, vagina, urethra and other places in the body.
Anal Cancer Types
Several types of tumors may be found in the anus. While some of them are malignant (cancer), others are benign (not cancer) or precancerous (may develop into cancer). The main types of anal cancer are:
Carcinoma in situ is early cancer or precancerous cells. They are only on the surface cells of the anal canal. This also may be called Bowen’s disease.
Squamous cell cancer (carcinoma) forms in the cells that line the anus. This is the most common type of anal cancer.
Adenocarcinomas develop in the glands around the anus.
Skin cancers, including basal cell and melanoma, often are found when they are in advanced stages.
Anal Cancer Risk Factors
Anything that increases your chance of getting anal cancer is a risk factor.
- Age: Squamous cell carcinoma of the anus most often is found in people older than 50
- Human papillomavirus (HPV) infection
- Human immunodeficiency virus (HIV) or acquired immunodeficiency syndrome (AIDS)
- Having more than 10 sexual partners
- Anal intercourse
- Frequent anal redness, swelling and soreness
- Tobacco use
- Immunosuppression, including taking immune-suppressing drugs after an organ transplant
Not everyone with risk factors gets anal cancer. However, if you have risk factors, it’s a good idea to discuss them with your doctor.
Anal Cancer Prevention
Certain lifestyle choices can help prevent anal cancer. One of the most important is to avoid HPV infection. Some ways you can lower your chances of getting HPV include:
- Wait until you are older to have sex and limit your number of sexual partners
- Use condoms during sex
- Avoid sex with people with sexually transmitted diseases (STD) or who have had multiple sexual partners
- Don’t smoke or use other types of tobacco
- Get an HPV vaccine. Gardasil® and Cervarix® help protect against certain types of HPV. But if you have HPV, they do not cure it.
Visit our Prevention site to learn more about preventing anal cancer.