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Sunday, November 23, 2014
The anus is the external opening of the rectum, the final length of the digestive system, and is located between the buttocks. Cancers of the anus are usually tumors that come from the wall of the 1.5 inch anal canal. There were on average 3089 new cases of anal cancer in women and 1678 in men diagnosed each year from 2004-2008, the majority of which (4500) are caused by human papilloma virus (HPV). Much like other cancers caused by HPV, the rate of anal cancer has continued to rise in the U.S., with the American Cancer Society estimating about 7,060 new cases (4,430 in women and 2,630 in men) in 2013 and over 800 deaths.
Women are more likely than men to get anal cancer, but black men are more likely to get the disease than black women, and anal cancer is more common in African-Americans in general. Other risk factors for anal cancer include:
Many of these factors are risk factors for chronic HPV infection of the anal canal.
The vast majority of people with HPV infections do not get anal cancer, but it is possible for an HPV infection to be spread from one part of the body to another. This means than an HPV infection may start in the genitals and then spread to the anus, making it possible to get anal cancer even if you have never engaged in anal sex.
Yes. Preventing infection with HPV is vital to preventing anal cancer. Some things you can do to help prevent anal HPV infection and reduce the risk of HIV infection include:
The vaccine Gardasil has been shown to prevent anal pre-cancers caused by HPV types 16 and 18, and vaccination is recommended for boys and girls, preferably at the ages of 11-12, to achieve immunity to HPV subtypes before the age of first sexual activity.
Most anal cancer cases are not diagnosed until they become symptomatic, with symptoms including
Some early cancers can be discovered during a digital rectal exam (DRE) that is performed with routine pelvic exams in women and during prostate exams in older men. An anal Pap test, similar to the Pap test performed for cervical cancer, can be used to look for anal intraepithelial neoplasia (AIN), an anal cancer precursor.
While some experts including the U.S. Department of Veterans Affairs and the New York State Department of Health advise screening for certain populations, there are no standard recommendations for anal cancer screening by the U.S. Preventive Service Task Force or Centers for Disease Control. This is due to a lack of quality research showing improved cancer outcomes from screening and treatment of anal cancer precursors.
Those at high risk for anal cancer, including men and women diagnosed with HIV, some men who have sex with men (MSM), women who have had cervical or vaginal cancer, and transplant recipients, should discuss with their doctors what screening is advised.
For help finding a provider in your area who provides anal cancer screening check the National LGBT Cancer Network Screening Facilites directory.
Prepared in partnership with Kyle Scarberry, MD, Class of 2013, Case Western Reserve University School of Medicine.
Learn more about anal cancer:
More information about the diagnosis, staging, and treatment of anal cancer and AIN can be found at the links below:
This article is a NetWellness exclusive.
Last Reviewed: Mar 18, 2013
Sara H Lee, MD
Assistant Professor of Pediatrics
School of Medicine
Case Western Reserve University