CROI 2020 Abstract eBook

Abstract eBook

Poster Abstracts

or LSIL seems to be the best strategy to triage candidates for HRA, with the highest AUC and the advantage of saving biomarker and HRA performance.

621 LOW ADHERENCE TO TREATMENT AND SURVEILLANCE OF HPV-RELATED ANAL PRECANCER Richard Silvera 1 , Michael Gaisa 1 , Yuxin Liu 1 , Ashish A.Deshmukh 2 , Keith M. Sigel 1 1 Icahn School of Medicine at Mt Sinai, New York, NY, USA, 2 University of Texas at Houston, Houston, TX, USA Background: Persons living with HIV (PLWH) have nearly 20-fold elevated risk of anal cancer compared to the general population. Several guidelines recommend annual anal cancer screening using anal cytology, high-resolution anoscopy (HRA) guided biopsies, and treatment of high grade intraepithelial lesions (HSIL), the precursors to anal cancer. Untreated HSIL can progress to invasive cancer and frequently recurs after treatment (>50%) necessitating longitudinal surveillance. Using data from our large screening cohort, we evaluated rates and predictors of adherence to surveillance HRAs following a diagnosis of anal HSIL. Methods: The Mount Sinai Anal Dysplasia Program is an HRA referral site for a large urban population of PLWH and HIV-uninfected MSM. We collected data on demographics, HIV clinical variables, and HRA attendance and outcomes from 2009-2019. We identified patients who were diagnosed with HSIL on first HRA and measured the following outcomes: (1) adherence to any follow-up, including repeat HRA or ablation, at any time after initial HSIL diagnosis; (2) follow-up examination within 18 months of HSIL diagnosis; (3) return for HSIL ablation within 6 months; (4) surveillance HRA following ablation. We also evaluated the predictors of these outcomes. Results: 3,646 unique patients underwent at least one HRA during the study. 387 patients (11%) had HSIL or cancer on initial HRA. Of this group, median age was 45, 92%were PLWH, 90%were male, 88%MSM, with diverse race/ ethnicity: 30%White, 23% Black, and 30% Hispanic. 202 patients (52% of the HSIL cohort; see Figure) underwent ablation. Median time to ablation from HRA was 49 days (10%were ablated >180 days). Of those who received ablation, 71% followed up at any time. Among those not receiving ablation, 27% followed up at any time. Among HSIL patients the only significant predictor of adherence to surveillance was Hispanic ethnicity (p=.02). 35% of patients diagnosed with HSIL never returned. Compared to Whites (69%), Hispanics were more likely to return (73%, p=.04), while Blacks (54%, p=.02) and PLWH with viremia (57%; p=.05) were less likely to return after HSIL diagnosis. Conclusion: Adherence to treatment and surveillance following an initial diagnosis of anal HSIL was poor in a large, urban anal cancer screening cohort. Future research to understand barriers and facilitators could inform interventions to improve adherence to anal cancer screening.

620 ANAL CANCER SCREENING: IS IT TIME FOR CYTOLOGY AND HIGH-RISK HPV COTESTING? Michael Gaisa 1 , Yuxin Liu 1 , John Winters 1 , Ashish A.Deshmukh 2 , Keith M. Sigel 1 1 Icahn School of Medicine at Mt Sinai, New York, NY, USA, 2 University of Texas at Houston, Houston, TX, USA Background: Anal cancer screening targets cancer precursors, defined as high-grade squamous intraepithelial lesions (HSIL). Current guidelines suggest an anal cytology (AC) severity grade of atypical squamous cells of undetermined significance or greater (≥ASCUS) as referral threshold for high-resolution anoscopy (HRA). This study sought to determine whether co-testing AC for high-risk human papillomavirus (hrHPV) improves screening performance and to compare the efficiency of two novel HRA referral thresholds to current clinical practice. Novel algorithm A sets the threshold for HRA referral at any hrHPV or AC with low-grade squamous intraepithelial lesion or greater (≥LSIL); algorithm B was recently proposed by Sambursky et al. Methods: Anal swabs were obtained simultaneously or within 3 months of HRA-guided biopsies and used for AC and Cobas® hrHPV DNA co-testing. Using biopsy-proven HSIL as an endpoint we calculated sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) as well as relative risk (RR) of HSIL for various AC/HPV co-testing combinations. Test characteristics were then compared between screening strategies using an efficiency frontier method. Results: 1,947 paired AC and hrHPV results from 1,268 individual patients were analyzed (89% HIV-positive, 90%MSM and 9.5%women). Adding hrHPV testing to the current AC referral threshold of ≥ASCUS increased sensitivity from 80.4% to 95.9% (p<0.001). Requiring HPV16/18 positivity for referral markedly improved specificity but decreased sensitivity. For each AC category, the RR of HSIL was substantially greater when any hrHPV was detected. When comparing screening strategies, sensitivity for the current guideline approach, algorithm A and B was 80.4%, 96.4%, and 86.9%, while specificity was 37.6%, 22.4%, and 35%, respectively (see table). When calculating number of missed HSILs versus number of unnecessary HRAs for a hypothetical cohort of 10,000 persons with 30% HSIL prevalence, all strategies including co-testing were found to be more efficient than those without. Conclusion: Co-testing AC for hrHPV improves the sensitivity to detect anal HSIL for all AC categories. Positivity for any hrHPV, especially types 16/18, implies a significant risk for anal HSIL. Algorithm A, combining ≥LSIL AC and reflex hrHPV testing for benign and ASCUS cytology results, may improve efficiency of anal cancer screening.

Poster Abstracts

622 ANAL PRECANCER SCREENING AMONG MSM: WHAT IS THE BEST STRATEGY? Jing Sun 1 , Dorothy J. Wiley 2 , Teresa Darragh 3 , Hilary K. Hsu 2 , Nancy Joste 4 , Stephen Young 5 , W. David Hardy 6 , Susheel Reddy 7 , Jeremy J. Martinson 8 , Gypsyamber D'Souza 1 , for the Multicenter AIDS Cohort Study (MACS)

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