Dear Doctor: I'm old enough to remember the shock over actress Farrah Fawcett's anal cancer diagnosis, which was not a disease you heard much about. Now I'm reading that this type of cancer is relatively common. Isn't there some kind of screening test?
Dear Reader: It's true that Farrah Fawcett made international news when she went public with her diagnosis of anal cancer in 2006. Due to taboos associated with its location in the body, anal cancer was seldom discussed. The actress made a point of publicly sharing her medical journey until her death three years later, and she was applauded for helping to ease the stigma associated with the disease.
Now, with the release of findings from a new study, anal cancer is in the spotlight once again. According to the study, which looked at data collected by U.S. cancer registries between 2001 and 2015, the incidence of the most common type of anal cancer rose 2.7% each year for the last 15 years. The researchers said this annual increase makes anal cancer one of the fastest-growing cancer diagnoses in the U.S., particularly among young black men and older women. The reason for this increase is not yet clear.
The public silence around anal cancer means that most people know very little about the disease. It's a relatively rare form of cancer, with about 8,300 new cases diagnosed each year. The disease is about twice as common in women as in men, and it occurs most often in people over age 50. Many are surprised to learn that the majority of cases — more than 90% — are caused by the human papilloma virus, or HPV. This is the same virus that we now know causes most cervical cancers, as well as many cancers of the penis, vagina and vulva. However, it is important to note that only a small fraction of those infected with HPV go on to develop cancer — in fact, there are more than 100 strains of the virus, but many are considered "low-risk."
Anal cancer occurs when abnormal cells begin to grow in the anal canal, the final segment of the large intestine. Symptoms of anal cancer include bleeding, stool mixed with visible blood, pain, the presence of a mass or growth, and more rarely, persistent itching. Several of these symptoms match symptoms of hemorrhoids. Hemorrhoids can usually be diagnosed with a visual and rectal exam. Anal cancer is diagnosed via a biopsy. In addition to age, race, gender and infection with HPV, risk factors for anal cancer include a history of smoking, anal sex with younger male partners, chronic inflammation and suppressed immunity due to disease or medical treatment.
Although there are no screening guidelines for anal cancer at this time, individuals who are at risk can talk to their doctors about tests or procedures. These include rectal exams and anal Pap tests. The HPV vaccine, which is recommended for both female and male adolescents, may also be helpful for adults in certain cases.
Eve Glazier, M.D., MBA, is an internist and associate professor of medicine at UCLA Health. Elizabeth Ko, M.D., is an internist and assistant professor of medicine at UCLA Health. Send your questions to email@example.com, or write: Ask the Doctors, c/o Media Relations, UCLA Health, 924 Westwood Blvd., Suite 350, Los Angeles, CA, 90095. Owing to the volume of mail, personal replies cannot be provided.