High-Resolution Anoscopy Referral Rates Adopting Different Anal Cancer Screening Strategies for Men Who Have Sex with Men

The International Anal Neoplasia Society (IANS) has generated recommendations for anal cancer screening, identifying men who have sex with men (MSM) living with human immunodeficiency virus (HIV; MSM-LWH) ≥35 years and MSM not living with HIV (MSM-noHIV) ≥45 years as groups to prioritize. As high-resolution anoscopy (HRA) availability is still limited across Europe, a retrospective study was conducted to estimate the potential HRA referral rates of the Sexually Transmitted Infections (STI)/HIV center of a European capital city using IANS-recommended strategies. The study included participants in a program for the surveillance of anal intraepithelial neoplasia and anal human papillomavirus (HPV) natural history. MSM-LWH ≥35 years and MSM-noHIV ≥45 years with valid results for liquid-based anal cytology and HPV test at baseline were included. The following strategies were evaluated: cytology as a standalone test or with high-risk HPV (hrHPV) triage; hrHPV (with/without HPV16 genotyping) as a standalone test or with cytology triage; and cotesting with cytology and hrHPV (with/without HPV16 genotyping). Overall, 307 MSM were included (244 LWH, 79.5%). hrHPV as a standalone test led to the highest referral rate in both MSM-LWH and MSM-noHIV (74.6% and 55.6%, respectively). Cytology with hrHPV triage (without genotyping) and hrHPV with cytology triage resulted in the same referral rates (44.3% in MSM-LWH and 27.0% in MSM-noHIV). In settings with insufficient HRA capacity, only high-grade squamous intraepithelial lesions (HSIL) or atypical squamous cells-cannot exclude HSIL (4.9% and 9.5% for MSM-LWH and MSM-noHIV, respectively) and HPV16+ MSM (27.0% and 20.6%, respectively) would be referred to HRA. Adoption of IANS recommendations should balance the sensitivity of the screening algorithm and the HRA referral rate because the latter is a matter of concern in settings with limited HRA capacity. Prevention Relevance: Adopting the recent IANS recommendations for anal cancer screening in MSM may be challenging when HRA availability is limited. Estimating the HRA referral rates we would have using 12 different screening algorithms, we highlighted that application of these recommendations implies a careful analysis of the local resource capacity.