CO2 laser therapy versus topical imiquimod for the treatment of vulvar high-grade intraepithelial lesions: A retrospective cohort study.

Objectives: To compare topical imiquimod with CO₂ laser therapy for the treatment of a first episode of vulvar high-grade squamous intraepithelial lesions (vHSIL), to identify serious adverse effects of both treatment modalities, and to examine risk factors for treatment failure.

Methods: This retrospective chart-based cohort study included 47 patients initially treated with topical imiquimod or CO₂ laser therapy between 2017 and 2021. The primary outcome was treatment failure, defined as the need for repeat treatment. Cumulative incidence curves were used to compare the probability of treatment failure over time by treatment group. Potential risk factors for treatment failure, including age, treatment type, lesion focality, and smoking, were examined using Cox proportional hazards models to estimate adjusted hazard ratios (aHRs) and 95% confidence intervals (95% CIs).

Results: Sixty-six percent (31/47) of patients were initially treated with topical imiquimod and 34% (16/47) with CO₂ laser. Both groups were similar in age, lesion focality, human papillomavirus vaccination, and smoking status. During a follow-up of 62.3 person-years, 52% (16/31) of patients treated with imiquimod and 56% (9/16) of patients treated with CO₂ laser experienced treatment failure. Age over 52 years was associated with a higher risk of treatment failure (aHR 3.07, 95% CI 1.25-7.53). The association was positive but not significant for multifocal versus unifocal lesions and for smokers versus non-smokers. No serious adverse effects were observed with either treatment modality.

Conclusion: Topical imiquimod has similar efficacy and safety to CO₂ laser therapy for initial the treatment of vHSIL. Older age is associated with an increased risk of treatment failure.