Tolerability, Safety, & Efficacy of Argon Plasma Coagulation to Treat Anal Intraepithelial Neoplasia in HIV-Positive Men

HIV infected men having sex with men (MSM) are at increased risk of developing anal cancer compared to the general population and the incidence continues to increase despite better control of HIV infection with HAART (Highly Active Anti-Retroviral Therapy). The causative agent is known to be Human Papilloma Virus infection which can lead to dysplastic changes in the anus, detectable by High Resolution Anoscopy with biopsies. The analysis of the abnormal tissue can then be graded as Anal Intraepithelial Neoplasia 1 to 3, with AIN 2 or 3 considered as high grade dysplasia. These lesions are cancer precursors, but the proportion of lesions progressing to invasive anal cancer and the time to event are unknown. There is currently no recognized treatment to offer as standard of care although it is of general belief that treating these lesions, as it is done for women with CIN 2 and 3 (Cervical Intraepithelial Neoplasia) could help decrease the number of progressions to invasive anal cancer in MSM infected with HIV.

By experience at our center and results of this technique for other gastrointestinal pathologies, we believe Argon Plasma Coagulation (APC) could be a safe, well tolerated and efficient treatment of high-grade dysplasia (AIN 2/3) in HIV infected MSM.

This study will assess the APC treatment in 20 patients, all HIV infected MSM, with established AIN 2/3 (as confirmed with their last two anal biopsies, at least 4 months apart). Patients will then be followed with regular High Resolution Anoscopies for two years. The primary objective is to assess if APC is a safe and well tolerated treatment method for AIN 2/3 in HIV-positive MSM. As secondary objectives, the efficacy of APC treatment on AIN 2/3 lesions in HIV-positive MSM, the number of treatments with APC necessary to obtain regression or resolution of AIN 2/3 over two years and the efficacy of APC treatment to decrease anal HPV in this population will also be addressed.

Inclusion criteria

• Age 18-65 years
• The last two High Resolution Anoscopies (HRA) of the patient, occurring at least 4 months apart, revealed histologic diagnoses of AIN 2 or 3
• HIV infected for at least 6 months
• Patient must be a man having sex with other men (currently or anteriorly).
• Able to provide a signed and dated Research Ethics Board (REB)-approved informed consent form (ICF) for the study

Exclusion criteria

• History of invasive anal cancer
• International normalized ratio (INR) > 1.5
• Platelet count < 50,000
• Previously (or currently) received chemotherapy or radiotherapy for AIN or anal cancer
• Currently receiving interferon or cidofovir treatment
• Diagnosed with circumferential (diffuse) high-grade AIN, or involving > 75% of the anal canal.