A trial of radiofrequency ablation for anal intraepithelial neoplasia

Purpose: Radiofrequency ablation (RFA) effectively treats esophageal high-grade dysplasia, but its efficacy in treating anal canal high-grade squamous intraepithelial lesions (HSILs) is unsubstantiated. This prospective study assessed the safety and efficacy of applying hemi-circumferential RFA to anal canal HSIL. Methods: Twenty-one HIV-negative participants with HSIL occupying ≤ half the anal canal circumference were treated with hemi-circumferential anal canal RFA. Participants were assessed every 3 months for 12 months with high-resolution anoscopy; recurrence in the treatment zone was re-treated with focal RFA. Results: Twenty-one participants with a mean of 1.7 lesions (range 1–4) enrolled and completed the trial. Six (29 %) participants had recurrent HSIL within the treated hemi-circumference within 1 year. Four participants (19 %) had persistence of an index lesion at 3 months. One (2.9 %) index HSIL persisted again at 12 months. No participants had more than two RFA treatments. KM curve-predicted HSIL-free survival within the treatment zone at 1 year was 76 % (95 % CI 52–89 %). Comparing the first 7 and last 14 participants, the predicted 1-year HSIL-free survivals are 43 % (95 % CI 10–73 %) and 93 % (95 % CI 59–99 %), respectively (p = 0.008), suggesting a learning curve with the treating physician. Multivariable analysis showed decreased recurrence in the last 14 participants (HR 0.02; 95 % CI 0.001–0.63) while increasing BMI increased recurrence (HR 1.43, 95 % CI 1.01–2.01). No participants had device or procedure-related serious adverse events, anal stricture, or heavy bleeding. Conclusions: Hemi-circumferential RFA yielded a high rate of anal HSIL eradication in HIV-negative patients at 1 year with minimal adverse events. Lesion persistence was probably related to incomplete initial ablation.