Anal Cancer

Anal cancer occurs when the cells within the tissues of the anus (the opening at the lower end of the intestines to the outside of the body) become cancerous. Anal cancer is very rare and highly treatable if diagnosed early. In recent years, the number of new cases has risen, though reasons for this remain unknown. While the cause of anal cancer is not entirely known, the disease has been linked to HPV (human papillomavirus) infection, the virus that also has been linked to cervical cancer. Most cases of anal cancer are discovered by the patient through self-observation in the early stages, creating a higher chance of survival.

Statistics

• In 2010, an estimated 5,260 new cases of anal cancer were diagnosed in the United States and an estimated 720 people died from the disease. Most new cases of anal cancer were diagnosed in women (3,260).
• HPV has been linked to an estimated 90 percent of anal cancers.
• Overall, about 66 percent of patients newly diagnosed with anal cancer are expected to survive more than 5 years.

Risk Factors

• Age: The majority of patients are diagnosed after age 50 and the risk of developing the disease increases with age. 
• Race: Caucasian women show the highest rate of diagnosis, and African-American men are diagnosed with anal cancer more than men of other races.
• Sex: Women have a higher incidence of anal cancer than do men. Women specifically are at higher risk if they begin having sex at an early age, have multiple sexual partners, and engage in anal sex. Such behaviors can increase risk for HPV infection, which also increases risk for anal cancer.
• Smoking: People who smoke are several times more likely to have anal cancer than nonsmokers. Quitting smoking eliminates harmful chemicals in the bloodstream and reduces risk.
• HPV: Exposure and infection can lead to anal and other types of cancer.
• Other cancers: Those who have cancer of the vagina, cervix, or vulva face an increased risk of the disease. This is due to the link between HPV and other cancers.

Symptoms and Signs
Symptoms of anal cancer are not always apparent. Most cases, however, are discovered early during rectal exams because of the cancer’s formation on an easily accessible part of the body. Physicians can also perform an anal Pap for high-risk patients or those showing symptoms. Warning signs may include:

• Anal bleeding or irritation
• Soreness
• Stools smaller in size
• Enlarged lymph nodes in the anal or groin region 
• Anal discharge
• Unusual anal discharge