Risk factorsBy Mayo Clinic staff
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. Men and women who have many sexual partners over their lifetimes have a greater risk of anal cancer.
- Anal sex. Men and women who engage in anal sex have an increased risk of anal cancer.
- Smoking. Smoking cigarettes may increase your risk of anal cancer. Former smokers have only a slightly elevated 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 disease that can also cause genital warts. HPV may cause cells in the anal canal to appear abnormal — a condition called anal squamous intraepithelial lesions (ASIL). The abnormal cells associated with ASIL aren't cancer, but they may develop into anal cancer. However, some people with ASIL never develop anal cancer.
- 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. Long-term use of corticosteroids, such as those prescribed to control autoimmune disorders, also may increase the risk of anal cancer. HIV — the virus that causes AIDS — suppresses the immune system and increases the risk of anal cancer.
- Deng GE, et al. Evidence-based clinical practice guidelines for integrative oncology: Complementary therapies and botanicals. Journal of the Society for Integrative Oncology. 2009;7:85.
- Anal carcinoma. Fort Washington, Pa.: National Comprehensive Cancer Network. http://www.nccn.org/professionals/physician_gls/PDF/anal.pdf. Accessed Oct. 19, 2010.
- Anal cancer treatment (PDQ). National Cancer Institute. http://www.cancer.gov/cancertopics/pdq/treatment/anal/patient. Accessed Oct. 19, 2010.
- Malik U, et al. Cancer of the anal canal. In: Abeloff MD, et al. Abeloff's Clinical Oncology. 4th ed. Philadelphia, Pa.: Churchill Livingstone; 2008:1557.
- Gardasil (prescribing information). Whitehouse Station, N.J.: Merck & Co. Inc.; 2009. http://www.merck.com/product/usa/pi_circulars/g/gardasil/gardasil_pi.pdf. Accessed Oct. 20, 2010.
- Cervarix (prescribing information). Research Triangle Park, N.C.: GlaxoSmithKline; 2009. http://us.gsk.com/products/assets/us_cervarix.pdf. Accessed Oct. 20, 2010.
- Joseph DA, et al. Understanding the burden of human papillomavirus-associated anal cancers in the U.S. Cancer. 2008;113(suppl):2892.
- Moynihan TJ (expert opinion). Mayo Clinic, Rochester, Minn. Oct. 28, 2010.