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 rare but treatable. In recent years, the number of new cases has risen. While the cause of anal cancer is not entirely known, the disease has been linked to HPV (human papillomavirus) infection, which is also linked to cervical cancer. Many cases of anal cancer can be found in the early stages when the cancer is most treatable, creating a high chance of survival.
Statistics
- In 2019, an estimated 8,300 new cases of anal cancer will be diagnosed in the United States, and an estimated 1,280 people will die from the disease. Women have a higher incidence of anal cancer than men, with 5,530 new cases expected in the U.S., compared to 2,770 for men.
- HPV has been linked to more than 91 percent of anal cancers.
- About 66 percent of newly diagnosed patients with anal cancer are expected to survive five years or more.
Risk Factors
- Age: The majority of patients are diagnosed between the ages of 50 and 80.
- HPV: Exposure and infection with HPV can lead to anal and other types of cancer.
- Anal warts: People with anal warts are more likely to develop anal cancer, although the warts themselves are unlikely to become cancerous.
- Weakened immune system: People with a weakened immune system, including those who have had transplants, those who take drugs to suppress their immune systems, and those with HIV or AIDS, are at higher risk.
- Sex: Having many sexual partners increases risk of contracting HPV and HIV, which also increases risk of anal cancer. Anal sex also increases risk of anal cancer.
- Smoking: People who smoke are more likely to have anal cancer than non-smokers. Quitting smoking eliminates harmful chemicals in the bloodstream and reduces risk.
- Other cancers: Those who have cancer of the vagina, cervix, or vulva face an increased risk of the disease. This is likely due to the link to infection caused by HPV. People treated with radiation to the pelvic area also have an increased risk.
- Chronic local inflammation: People with anal fistulas or open wounds have a slightly higher risk.
Symptoms and Signs
Symptoms of anal cancer are not always apparent. Many 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 test or digital rectal exam (DRE) for high-risk patients, or those showing symptoms. Warning signs may include:
- Anal bleeding or itching
- Pain in the area
- Feeling of fullness in the area
- Narrower stools or change in bowel habits
- Unusual anal discharge
- Enlarged lymph nodes in the anal or groin region
- Mass or lump in the area
Tips for Prevention
Although some people with anal cancer have no risk factors, there are steps that men and women can take to help reduce their risk for the disease. The most effective prevention method is to avoid HPV infection through an HPV vaccine. Condoms have been shown to reduce risk, but cannot eliminate it completely due to the possibility of skin contact. Treating HIV can help control the infection and lower the risk for developing anal cancer. Since smokers face an increased risk, avoiding tobacco may also help reduce risk.
Treatment
Anal cancer is a very treatable cancer, especially if identified in the early stages. Treatment options vary depending on how advanced the cancer is and if it has spread to other parts of the body. Physicians will determine the most appropriate treatment for each patient, but potential treatment options include surgery, radiation therapy, or chemotherapy. A combination of two or more of these treatments may be used to provide the best chance of disease control.
Sources: American Cancer Society, American Society of Clinical Oncology, American Society of Colon and Rectal Surgeons, Centers for Disease Control and Prevention, and National Cancer Institute