13. Long-term effectiveness of intra-anal high-grade dysplasia ablation and near 100% prevention of progression to anal cancer

Abstract

Background: High-grade dysplasia (HSIL) is the anal squamous cell carcinoma (ASCC) precursor. Ablation with surgery, electro cautery (ECA) and infrared coagulation (IRC) might prevent ASCC. We endeavoured to determine long-term effectiveness of HSIL ablation and progression to ASCC. Methods: A retrospective chart review of patients undergoing HSIL ablation by any modality between February 1998 until May 2012. Results: In 456 HIV+ MSM (mean age 45 ± 9 years) and 271 HIV– MSM (mean age 41 ± 11years) followed for a mean of 3 (range 0.2–13) years, 1673 HSILs were treated by laser, IRC and/or ECA. ASCC developed in 5 (0.7%) MSM but only one (0.1%) was undergoing active treatment. For HIV+ MSM, recurrence after 1st, 2nd, 3rd and 4th treatment was 66%, 64%, 62% and 54%, respectively. For HIV– MSM, HSIL recurrence after the 1st, 2nd, 3rd and 4th treatment was 59%, 44%, 46% and 50%, respectively. Median number of recurrent lesions was never greater than 2 for HIV+ MSM and 1 for HIV– MSM. The cure rate of lesions treated once in HIV+ and HIV– MSM was 73% and 84%, respectively. KM curves demonstrate that most recurrence occurs within the first 12 months after treatment. Recurrence increased with HIV infection (HR 1.3; 95% CI: 1.1–1.6) and each additional lesion treated (HR 1.6; 95% CI: 1.1–1.2). Age and treatment modality did not affect recurrence. Conclusions: Patients undergoing active ablation for cure of intra-anal HSIL appear to have limited progression to ASCC. Recurrence remains high but falls over time and repeated treatment.