Anal intraepithelial neoplasia (AIN) and 89-100% of anal cancers are caused by persistent infections with high-risk (HR) human papillomaviruses (HPV). In HIV-positive patients, anal HPV infection and AIN are very common and these patients have a greatly increased risk of developing anal cancer. However, a continuous increase in the incidence of anal cancer has also been observed in the general population in recent decades. AIN can clinically present in diverse manners. In HIV-positive patients AIN can be hidden in condylomas. Furthermore, 3-14% of high-grade AIN progress to anal cancer within 5 years. Therefore, screening examinations should be offered to patients with an increased risk for anal cancer. The treatment options for AIN are similar to those for condylomas. HIV-positive patients with controlled immune status and HIV-negative patients with anal cancer respond comparably well to combined radiochemotherapy. A German-language AWMF S3 guideline for anal cancer will be available in 2020. In HIV-positive patients over 26 years of age, HPV vaccination showed no effect in a controlled phase‑3 study. To prevent AIN and anal cancer in the future, HPV vaccination rates need to be increased in HPV-naïve girls and boys.
Keywords: Anal intraepithelial neoplasia; Cancer screening; HIV seropositivity; HPV vaccines; Human papillomavirus.