Short-term effectiveness and tolerability of carbon dioxide laser for anal high-grade squamous intraepithelial lesions in individuals living with HIV

Background: Ablative treatment of intra-anal high-grade squamous intraepithelial lesions (HSIL) reduces the risk of progression to anal squamous cell carcinoma. Our objective was to assess the short-term effectiveness and tolerability of the carbon dioxide laser for treating intra-anal HSIL in patients at high risk of anal cancer. Methods: This is an exploratory, pilot, single-arm, clinical trial of treatment response for anal HSIL in people living with HIV diagnosed with ≤3 not previously treated HSILs. Individuals were treated with one carbon dioxide laser treatment session. Clinical assessment by high resolution anoscopy and systematic recording of adverse events was performed. Results: Fifty-two patients with 72 HSILs were included. Response to treatment was assessed in 48 (92.3%) patients; in the per-protocol population analysis, complete, partial, and no response was seen in 50% ( n = 24), 20.8% ( n = 10) and 29.1% ( n = 14), respectively. Being older than 40 years and having a CD4 T-cell count lower than 200 cells/μL at diagnosis of HSIL were significantly associated with a poor response to treatment. Data on adverse events was recorded for 49 patients and 69.4% ( n=34) reported no symptoms after the procedure. Conclusions: Carbon dioxide laser ablation is a promising and well tolerated treatment for intra-anal HSIL.