Aims: To assess the effectiveness and safety of infrared coagulation (IRC) for the ablation of anal intraepithelial neoplasia (AIN) and to provide data on the prevalence of AIN in HIV-infected patients.
Patients and methods: We performed a single-center, retrospective cohort study based on data collected from a prospectively compiled database of outpatients attended in the Clinical-Proctology-HIV-Unit (first visit). The effectiveness (normal anal cytology after 12 months of IRC) and safety of IRC were estimated.
Results: Between January 2005 and December 2011, a total of 69 (5%) patients with biopsy-proven AIN-2 or AIN-3 from among 1518 patients (1310 men; 208 women) were treated with IRC. The prevalence of cytological abnormalities was 49.5% [751/1518; (atypical squamous cells of unknown significance, 14%; low-grade squamous intraepithelial lesions, 27.5%; high-grade squamous intraepithelial lesions, 8%)]. High-resolution anoscopy revealed intra-anal condylomata in 31% of patients (236/751), nonvisualized lesions in 30% (227/751), and visualized lesions (from which biopsy specimens were taken) in 38% (288/751). The histological diagnosis was: AIN-1, 52% (151/288); AIN-2, 15% (44/288); AIN-3, 9% (25/288); normal, 19% (56/288); and nonevaluable, 4% (12/288). IRC was applied in-office in 66 patients (three refused to undergo treatment). At 12 months, all patients (n = 56) had a normal anal cytology result. Seven (13%) patients had biopsy-proven recurrence [mean (range) time-to-recurrence, 30 (18-43) months]. High-risk-human papilloma virus (HPV) infection was detected in all anal lesions (HPV-16 was the most common genotype). Agreement between cytological and histological results was poor.
Conclusion: A high prevalence of AIN was found in both HIV-infected men and HIV-infected women. Although randomized clinical trials are lacking, IRC ablation of AIN-2 and AIN-3 lesions without concomitant condylomata could help prevent anal squamous cell carcinoma.