Ask Dr. H: Most anal cancer is linked to HPV

Question:

I've heard the news that Farrah Fawcett has anal cancer and it has spread to her liver. What causes anal cancer? Is it from HPV (human papilloma virus)?

Answer: We're not sure the cause of all forms of anal cancer - and don't know details of Fawcett's case - but most cases seem to be associated with the human papilloma virus (HPV), the same virus responsible for virtually all cases of cervical cancer.

HPV causes genital warts, but most folks infected with HPV do not have genital warts. Also, most folks who have a diagnosis of HPV or genital warts do not develop anal cancer. The biggest risk factor for acquiring HPV is anal intercourse with a person infected with the virus.

HPV is but one part of the anal-cancer puzzle. The American Cancer Society points out that there are many studies that have found an increased rate of anal cancer in smokers, and the effect of smoking is especially important in people with other risk factors for anal cancer. Any condition that leads to a weakened immune system may trigger, in the presence of HPV, the development of anal cancer. This includes HIV/AIDS or any medical condition that requires the use of powerful immune-suppressing drugs.

Despite the prevalence of HPV and smoking, anal cancer is fairly rare - just over 5,000 new cases in the United States in 2008.

Anal cancer is found mainly in adults, with the average age being in the early 60s. The disease affects women somewhat more often than men. While the treatment for anal cancer is often very effective, an estimated 680 folks died of anal cancer in 2008.

With respect to Fawcett's illness, we do not know the particulars. And some folks with anal cancer do not have any known risk factors, and the cause remains unknown.

nolead begins

Q:

I developed a very painful sore draining from my tailbone which my doctor diagnosed as a "pilonidal cyst." I'm going to have it looked at by a surgeon. What is it? What causes them?

A: "Pilo" in Latin means "hair," and "nidal" in Latin means "nest." Although it's referred to as a cyst filled with pus and hair, it's technically an abscess. Pilonidal abscesses develop at the base of the spine at the uppermost part of the buttock cleft. They are very painful, making it difficult to sit. They may even cause fever.

What causes a pilonidal abscess to occur in the first place? There's no one answer for that. Some folks are born with them, only to develop an infection and drain to the surface at some point in life. Despite what has been popular teaching, that isn't how most pilonidal cysts develop.

It's believed that most pilonidal-cyst abscesses develop as a result of an infected, inflamed hair follicle and shaft. Another explanation is that some folks develop them as a result of a stray hair from another part of the body becoming embedded in a skin pore in the tailbone area, causing inflammation and infection. These abscesses also tend to run in families.

Regardless of the cause, the treatment is an antibiotic, usually followed by an open incision of the abscess, followed by a cleaning out of its contents. The space is then packed with gauze and allowed to heal from the inside out. Be patient; this may take months. Despite this treatment, some folks do get recurrences. A good overview of pilonidal cysts can be found at www.pilonidal.org.