The iconic photo of Farrah Fawcett smiling in a red swimsuit marked her as the face of sexy, natural beauty in the 1970s.
Now, after her death Thursday at age 62 from anal cancer, her fight against the illness may help give a face to a potentially stigmatizing condition that can be the result of infection with the human papilloma virus (HPV), a sexually transmitted infection.
"This does not mean that she was promiscuous," noted Dr. Jay Brooks, chairman of the department of hematology and oncology at Ochsner Clinic Foundation and Hospital in Baton Rouge, La. "It simply means that she, at some point in her life, was probably exposed to the human papilloma virus."
Indeed, estimates for the percentage of anal cancers as a result of infection with HPV ranges from 45 to 90 percent. Although the exact cause of anal cancer is not known, the American Cancer Society reports that most anal cancers seem to be linked to HPV infection.
And HPV, the most common sexually transmitted infection in the U.S., is associated with a number of other cancers, including cervical and oral cancers. High risk HPV types accompany about 99 percent of cervical cancer cases.
While HPV infection seems to be important in the development of anal cancer, the vast majority of people with HPV infections -- about 20 million Americans -- do not get anal cancer.
A 2007 study from the CDC determined that one in four females between 14 and 59 were infected with HPV, which is equivalent to 25 million American girls and women. Since only a small fraction of the millions of women affected with HPV develop anal cancer, risk factors beyond sexual activity, including smoking, a genetic predisposition to cancer, or being over 50, must be at play.
A great deal of research is underway to learn how HPV might cause anal cancer. There is good evidence that HPV causes many anal squamous cell carcinomas. But the role of this virus in causing anal adenocarcinomas is less certain.
"This was not necessarily the result of a sexually transmitted disease, and if it is, so what?" said Dr. Otis Brawley, chief medical officer of the American Cancer Society. "We need to not stigmatize this disease and the people who have it."
Anal cancer is rare -- much less common than cancer of the colon or rectum. The American Cancer Society estimates that in 2009 about 5,290 new cases of anal cancer will be diagnosed in the United States. The number of new anal cancer cases has been on the rise for many years.
But the stigma, coupled with the rarity and the cancer's location, may make those affected slower to respond to symptoms.
"For some people, this stigma is a critical factor in determining how quickly they respond to the symptoms or signs of disease," said Dr. Richard Wender, national president of the American Cancer Society, at the time Fawcett was diagnosed in 2006. "Just out of embarrassment, some people don't go to the doctor and say they have a pain in their anal area or that they have bleeding there."
Anal cancer can be a serious condition and the symptoms, which include changes in bowel habits, bleeding and pain, are not specific to anal cancer, making it difficult to catch in the early stages and almost impossible to prevent. An estimated 710 people (450 women and 260 men) will die of anal cancer in 2009, according to the ACS.
But treatment for anal cancer is often very effective, and most patients with this cancer can be cured. Fawcett's openness about her anal cancer, which included a documentary about her experience that aired in May, raised awareness about the disease.
"Her openness and honesty about this disease has probably helped to heal a lot of people. So she may have done a significant service by doing that," Brooks said. "You've got a woman who was known as a sex symbol who had a great deal of inner character and helped a great deal of other people."
ABC News' Joanna Schaffhausen contributed to this report.