Anal cancer is a relatively rare disease. However, it is strongly associated with anal human papillomavirus infection, whose prevalence has increased in the last years, especially in some groups like homosexuals and HIV-positive persons.
Human papillomavirus is one of the most frequent sexually transmitted diseases. During the life, more than three quarters of sexually active population are infected at least with one type of papillomavirus.
Most of papillomavirus infections clear spontaneously, however persistent high-risk human papillomavirus 16 is responsible approximately for 70 % of all cases of anal cancer. Generally, HPV infection in ano-genital region is becoming increasingly prevalent due to decreasing age of sexual debut and increasing lifetime number of sexual partners.
Therefore, more cases of anal as well as vulvar and vaginal cancer and their pre-malignant stages - anal, vulvar and vaginal intraepithelial neoplasia - can be expected in the future.