Article Text
Abstract
Anal cancer is an increasing problem among patients with HIV, especially among HIV-positive men who have sex with men (MSM) with incidence rates 100 per 100,000 person-years. This is much higher than the incidence of cervical cancer in HIV-negative women before standard cytological screening was introduced. Therefore, routine screening for anal premalignant lesions is subject of discussion. As with cervical cancer, anal cancer is preceded by a precursor called anal intraepithelial neoplasia (AIN).
In this presentation I will discuss the standard therapeutic options practiced to treat AIN lesions with the goal to prevent progression towards invasive carcinoma. Electrocauterisation is the most used option to date for AIN lesions. Other ablative measures are infrared coagulation, highly concentrated trichloroacetic acid, and liquid nitrogen. Whereas ablative therapy has to be performed in an outpatient clinical setting by trained health workers, patient administered home based treatment options have been studied also, like imiquimod, and 5-fluorouracil cream. Until now most treatment modalities have been studied in open label and/or non-randomised trials, and very little comparative studies have been performed. Therefore, scarce evidence-based data on the treatment of AIN is available. It is likely that intra-anal versus perianal AIN disease requires different treatment approaches.
So far, most AIN treatment studies show high recurrency rates, irrespective of the modality used. Novel treatment options are therefore looked after. Vaccination studies, using both preventive and therapeutic vaccines are ongoing. Preventive vaccines, targeting the causative HPV virus have been tried to prevent recurrent disease in successfully treated AIN patients. In established disease, HPV preventive vaccines are not believed to be effective since HPV E6 and E7 viral genes by then are incorporated in the host genome. Therefore, therapeutic AIN vaccines will need to target the transfected cell directly. Studies with E6 and/or E7 DNA targeting vaccines are ongoing.