[Diagnostics, treatment and aftercare of anal cancer].

Despite the increasing incidence, anal cancer is still a rare gastrointestinal tumor, so that due to the broadness of the primary care there is often little experience in the care of affected patients. Squamous cell cancer (SCC) constitutes more than 90% of all anal cancers and is nearly always associated with an infection by the human papillomavirus. This article concentrates on SCC of the anal canal and anal margin. The focus is on the primary diagnostics, surgical treatment, response assessment and aftercare. Treatment is carried out according to the decision of the interdisciplinary tumor board, independent of the tumor location and stage. Anal margin cancer in stage I (and IIa) can be successfully treated by an R0 excision. Combined chemoradiotherapy as the standard treatment in stages II and III is briefly summarized. The article is essentially based on the new German S3 guidelines on anal cancer.