ATLANTA — In a perverse twist of medical fate, Farrah Fawcett has become the poster girl for anal cancer, a rare disease often linked to a sexually transmitted virus.

Before her death last week, at age 62, the actress had come to terms with the illness and agreed to have her suffering and treatment chronicled for a television documentary.

"She knew that she had the kind of anal cancer that she wasn't going to ultimately overcome, and decided to leave as much of a legacy of awareness as she possibly could," her doctor, Dr. Lawrence Piro, said June 30 before the funeral.

It is an unexpected legacy for Fawcett, whose feathered hair and electric smile once dominated TV screens. A sexy photo of her in a red swimsuit, taken in the 1970s, was the top-selling pinup of all time. Despite her fame and work as an entertainer, friends say she was protective of her privacy.

But she was stricken by anal cancer, a rarely discussed affliction with symptoms that are sometimes mistaken for hemorrhoids. After tabloids began reporting on her illness, her family acknowledged it and a friend produced "Farrah's Story," a documentary that aired in May showing her treatment and suffering.

It was important new information for people unfamiliar with the disease or reluctant to even talk about it, some health officials said.

Breast cancer, prostate cancer and colon cancer were all once unmentionable diagnoses that gradually became commonly discussed, thanks in part to celebrity disclosures from people like First Lady Betty Ford, golfer Arnold Palmer and CBS news anchor Katie Couric, whose husband died of colon cancer.

But the anus is associated not only with defecation but also a taboo form of sex, observed Dr. Barron Lerner, a Columbia University physician who wrote "When Illness Goes Public: Celebrity Patients and How We Look at Medicine."

Lerner, an internist, said he and his patients frequently have conversations about different cancers and their potential risk factors. But anal cancer? Anal sex? "I never talk about that with my patients. It's something that might freak a lot of people out," he said.

However, in the wake of Fawcett's illness, it's likely that some patients will ask about her case and those topics will be discussed, he said.

To be sure, anal cancer is rare. About 5,000 cases are diagnosed each year in the United States, and there are about 700 deaths, according to the American Cancer Society.

The cancer is often associated with gay men who have anal sex and immune systems weakened by HIV or other conditions. But actually, more than half of the diagnoses and deaths occur in women.

It's unclear whether Fawcett's story will have any effect on promotion of a vaccine that targets HPV, human papilloma virus, which is blamed for cervical cancer and linked to most anal cancers.