Can photodynamic therapy be the preferred treatment option for anal intraepithelial neoplasia? Initial results of a pilot study.

Anal intra-epithelial neoplasia (AIN) is a pre-malignant condition, which over time may progress to invasive anal squamous cell carcinoma. There is no standard treatment for AIN, but one of the therapeutic options available is photodynamic therapy (PDT). There are very few published studies of the efficacy of PDT, but it has been shown to produce downgrading of high-grade dysplasia in the anal region. The aim of the study was to evaluate the role of PDT in the treatment of AIN. Fifteen patients who received anal PDT between 2004 and 2013 were identified; twelve of these had AIN, two had intra-epithelial adenocarcinoma and one had dysplasia with high-risk human papillomavirus. After a median follow-up of nineteen months, ten of these have had at least one follow-up with aceto-white staining. Six of these ten patients had a complete response to PDT, although three subsequently had some recurrence. Three further patients had a partial response to PDT. There were no major therapeutic complications. Our findings suggest that PDT is a safe and feasible treatment option for AIN, associated with reasonable response rates and relatively little morbidity. Further research into the efficacy of PDT for AIN is required.