Five-year evaluation of Anal Cancer Screening Program in Men Who Have Sex With Men with HIV at Two Academic Center Clinics

Abstract Background Guidelines recommend annual anal cytology-based squamous cell carcinoma of anus (SCCA) screening for men who have sex with men (MSM) with HIV aged ≥35 years (eligible population). Recommended threshold for high resolution anoscopy (HRA) depends on its availability: low-threshold (any abnormal cytology) if availability is high, and high-threshold (High-Grade Squamous Intraepithelial Lesion (HSIL) on cytology) if availability is low. Methods Retrospective chart review (2018-2022) at academic HIV clinics. We evaluate (i) 5-year uptake of cytology based SCCA screening in eligible population; (ii) estimate HSIL detection rate based on our current low-threshold criteria, and if high-threshold criteria were used for HRA referral. Results Of 432 eligible individuals, only 219 (50.7%) had at least one, and only 113 (26%) had >1 SCCA screening tests in a median followup of 4 years. N=74 (17.1%) of individuals had at least one abnormal anal cytology during follow-up, of which 56 (75.6%) received HRA. Increasing age (≥57 years) and history of smoking negatively correlated with ever receiving screening. Anal cytology (365 tests in 206 individuals) showed: 17.5% ‘unsatisfactory’, and 26.8% with any abnormal cytology (zero with HSIL) triggering HRA referral. Only 34 individuals (7.8% of screening eligible) were ever detected with HSIL. Strictly using high-threshold criterion for HRA referral would have led to no HRA or HSIL detection. Conclusions We noted poor uptake of screening over time, particularly in older age groups. Importantly, anal cytology performed poorly as a triage test for HRA referral: high rates of ‘unsatisfactory’ samples and low sensitivity for detecting HSIL.