Epidemiology of human papillomavirus infection.

Anogenital human papillomavirus (HPV) infection is a sexually transmitted disease (STD) that typically follows a self-limiting transient course for both sexes. The HPV incidences and prevalences vary greatly, because they reflect the sexual activity of the individuals studied and of the population they are in contact with. Higher prevalences are seen in young, sexually active groups and in high-risk areas for cervical and penile cancer, e.g. in Colombia. There has also been an increasing trend with time in Western Europe, paralleling the spread of other STDs and changes in sexual behavior. Penile intraepithelial neoplasia is usually positive for high-risk HPV DNA, mostly of type 16, whereas only approximately 50% of invasive penile cancers are positive for HPV DNA. This is similar to the role of high-risk HPV in vulvar carcinoma, where the attributable proportion is also approximately 40-50%. Moreover, in both sites similar histologic types of squamous cell carcinoma, i.e. the basoloid and basaloid/warty types, are mainly associated with high-risk HPV types. The studies performed so far have indicated that HPV has an etiological role in penile cancer, although the attributable proportion may be only approximately 40-50%.