Short-term efficacy and safety of CO2 laser vaporization for anal intraepithelial neoplasia

Objective To evaluate the short-term efficacy, safety, and human papillomavirus (HPV) clearance outcomes of carbon dioxide (CO 2 ) laser vaporization in patients with anal intraepithelial neoplasia (AIN), and to identify independent predictors of persistent postoperative HPV infection. Methods A retrospective cohort study was conducted on 99 patients who underwent CO 2 laser ablation for AIN at the Obstetrics and Gynecology Hospital of Fudan University between October 2023 and October 2024. Patients were categorized into four groups based on lesion location (perianal vs. anal canal) and histological grade (low-grade vs. high-grade). Operative parameters, response rates, HPV clearance rates, and complications were systematically analyzed. Results Among 99 enrolled patients, 7 were lost to follow-up, leaving 92 cases for final analysis. With a mean follow-up of 9.96 months, the overall 3-month treatment response rate was 85.9% (79/92), and the high-risk HPV clearance rate was 70.7% (65/92). No severe complications such as anal stenosis, incontinence, or mucosal erosion were observed during follow-up. Only 5 cases (5.4%) developed mild perianal redness, which resolved with topical antibiotics. Multivariate logistic regression identified preoperative HPV16/18 infection (OR = 3.62, 95% CI: 1.41–9.28, P = 0.007), high-grade lesions (OR = 2.95, 95% CI: 1.13–7.71, P = 0.027), and multifocal lesions (OR = 2.43, 95% CI: 1.02–5.80, P = 0.044) as independent risk factors for persistent postoperative HPV infection. Conclusion CO 2 laser vaporization demonstrates promising short-term efficacy and a favorable safety profile for treating AIN, and can be considered as an effective short-term local ablative option, though long-term prospective validation is needed. Rigorous surveillance for persistent HPV16/18 infection is warranted, and extended follow-up is required to assess long-term recurrence dynamics.