Faber MT, et al. - Researchers used data from nationwide, population-based Danish registries, to determine anal cancer risk after a diagnosis of benign anal disease and anal intraepithelial neoplasia (AIN). They followed a cohort of 126,174 people with either non-neoplastic anal disease or AIN 1-3 until the first occasion of anal cancer. Findings revealed a rise in the risk of anal cancer with increasing severity of lesions, reaching 4% five years following diagnosis of AIN3. High anal cancer risk was particularly observed in HIV-positive individuals. A significantly higher anal cancer risk was observed even among those with non-neoplastic anal lesions, especially inflammatory lesions when compared with that expected from Danish national anal cancer rates. In order to prevent both high-grade AIN and anal cancer, the importance of vaccination against human papillomavirus was suggested.