[Anal intraepithelial neoplasia and anal carcinoma: an increasing problem in HIV patients].

Anal dysplasia is common in HIV patients, especially in HIV-positive men having sex with men (MSM). High-grade anal dysplasia can progress to invasive anal cancer. As in cervical carcinoma, there is a cause and effect relationship between anal cancer and human papillomavirus (HPV) infection, especially with high-risk types such as HPV16. Several experts have recommended screening programs for anal cancer, including anal cytology along the lines of the Pap smear in women. Such screenings should only be performed if pathological findings result in further diagnostic steps and, if necessary, appropriate treatment. Clinical inspection, lesion biopsy, and treatment of anal dysplasia are performed under high-resolution anoscopy. Anal cancer is divided into cancer of the anal margin and cancer of the anal canal. This classification is important because of the difference in treatment regimens. Early cancer of the anal margin is excised akin to squamous cell cancer of the exposed skin, whereas cancer of the anal canal is treated by radiochemotherapy. HIV-positive and HIV-negative patients have similar response rates to combined radiochemotherapy. However, side effects, especially acute post-irradiation skin toxicity, early local recurrences, and abdominoperineal rectal excision are more common in HIV-positive patients. Physicians working in the field of HIV/AIDS should regularly screen their patients for the presence of anal dysplasia and anal cancer. Basic diagnostic workup includes clinical inspection of the perianal area, digital rectal examination, and anal cytology.