Five-Year Evaluation of an Anal Cancer Screening Program in Men Who Have Sex With Men With HIV at 2 Academic Center Clinics.

Background: Guidelines recommend annual anal cytology-based squamous cell carcinoma of anus (SCCA) screening for men who have sex with men with HIV aged ≥35 years (eligible population). The 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: This was a retrospective chart review (2018-2022) at academic HIV clinics. We evaluated (1) 5-year uptake of cytology-based SCCA screening in the eligible population and (2) estimated 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 1 and only 113 (26%) had >1 SCCA screening tests in a median follow-up of 4 years. Seventy-four (17.1%) individuals had at least 1 abnormal anal cytology during follow-up, of whom 56 (75.6%) underwent 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 criteria 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, with high rates of "unsatisfactory" samples and low sensitivity for detecting HSIL.