Objectives: To investigate treatment outcome of high-grade anal intra-epithelial neoplasia (AIN 2/3).

Methods: Review of all patients treated for AIN 2/3 with a minimum of 3 years of follow-up.

Results: Seventy two cases of AIN 2/3 fulfilling the criteria were identified. 81.9% of patients had ablative treatment using a diode laser under local anaesthesia. The median duration of follow-up was 60 months (range 36 - 164). 63.9% of patients were HIV positive. None of the patients (0%) developed invasive anal squamous carcinoma (anal cancer). Recurrence of AIN 2/3 was common, though less extensive after initial treatment. All recurrences were treated. Following treatment no patient developed sphincter dysfunction or needed colostomy. Two patients declined treatment and subsequently developed anal cancer.

Discussion: There is increased incidence of anal cancer amongst HIV positive people, especially in MSM and with added risk in those positive over 15 years. Cervical cancer, caused by the same HPV types as anal cancer, is successfully controlled through treatment of cervical intra-epithelial neoplasia (CIN 2/3). Three clinical observational studies demonstrate the evolution of anal cancer from AIN 2/3, despite some intervention, in 8.6% to 17.8% over 5 year (median) period of follow-up. In our cohort that underwent treatment for AIN 2/3, no one developed invasive anal cancer. More studies of treating anal intra-epithelial neoplasia are needed firstly to replicate our results and secondly to assess whether high-resolution anoscopy (HRA) services can produce similar outcomes to colposcopy treatment centres in cervical cancer prevention programmes.

Figure 1

Conclusion: Through this study we demonstrate the feasibility of anal cancer prevention, in at-risk groups, by treating high-grade anal intra-epithelial neoplasia.