Human papillomavirus as a cause of anal cancer and the role of screening

Anal cancer is a serious health problem in HIV-positive men who have sex with men, and precursor lesions, anal intraepithelial neoplasia, are well defined. Given the similarities with cervical cancer, screening for and treatment of anal intraepithelial neoplasia might prevent anal cancer. Screening programmes should meet the Wilson and Jungner criteria. We used these criteria to evaluate the current body of evidence supporting a screening programme for anal dysplasia. The natural history of anal intraepithelial neoplasia is gradually becoming more clear, and three prospective studies are now being performed to conclusively address this issue. High-resolution anoscopy stays the gold standard to diagnose anal intraepithelial neoplasia. The International Anal Neoplasia Society has recently published Practice Standards in the Detection of Anal Cancer Precursors. The main issue, however, is treatment. Although response rates are reasonable at early evaluation, the majority of patients has a recurrence. At present, an anal cancer screening programme for HIV-positive men who have sex with men meets most of the Wilson and Jungner criteria. Given that high-resolution anoscopy is the gold standard for screening, important issues that need addressing are the need for a less invasive screening procedure and the cost-effectiveness of screening. The main issue is treatment. Development and evaluation of new treatment strategies are essential for an effective and sustainable screening programm