Anal cancer represents less than 2% of gastrointestinal cancers, and 6% of ano-rectal cancers. Its incidence seems to be higher among women, people aged 60 years or older, and homosexuals affected by human immunodeficiency virus (HIV). In recent years, however, the incidence of anal cancer has increased. It is estimated that in 2008 about 5.070 new cases of anal cancer were diagnosed in the United States, with a total of about 3.000 in women and 2,000 in men. The number of deaths was estimated at 680; two thirds of those patients were over 65 years old.