Abstract 2241: Evaluating anal cancer screening approaches in high-risk populations in Puerto Rico
Authors: Keller Kandyce G. , Pearce Celeste Leigh , Ortiz-Ortiz Karen J. , Ramos-Cartagena Jeslie M. , Guiot Humberto , Colón-López Vivian , Deshmukh Ashish A. , Tirado-Gómez Maribel , Ortiz Ana Patricia 
Published: June 2022

Abstract
Introduction: Anal cancer incidence has been rising rapidly in Puerto Rico. The ANCHOR study showed that treating high-grade squamous intraepithelial lesions (HSILs) significantly reduces anal cancer incidence. Limited research has been done to understand the validity and associated costs of screening tools used to detect anal lesions in Hispanic populations. We aimed to evaluate the clinical performance (sensitivity, specificity, positive predictive value [PPV], and negative predictive value [NPV]) and screening test costs in the clinic-based sample. Understanding the accuracy and costs of screening tools can guide interventions in resource-limited settings to broaden the availability of effective, low-cost screening options and promote anal cancer prevention.
Methods: The cross-sectionally analyzed data was collected (May 2015 - June 2021) by the Anal Neoplasia Clinic of the University of Puerto Rico Comprehensive Cancer Center. The clinic predominantly serves referred adults (≥18 years old). Patients were included in the analyses if they had complete results for anal cytology, high-resolution anoscopy (HRA) with biopsy, and anal high-risk HPV (HR-HPV) typing (n=436). Sensitivity, specificity, PPV, and NPV were estimated to evaluate the clinical performance of anal cytology alone and in combination with HR-HPV typing in the detection of histologically confirmed anal HSIL (Gold standard). Analyses were stratified by risk group (women, MSM, and heterosexual men) and HIV status. Evaluation of cost-effective alternative screening strategies is currently ongoing.
Results: The mean age of our sample was 44 ± 13 years; more than half (67%) were male. HIV-infected MSM, HIV-infected women, and HIV-negative MSM comprised 45.4%, 22.2%, 13.3% of our sample, respectively. 40% of the sample had HSIL and 69% tested positive for HR-HPV. Measured against the gold standard, we found that co-testing (anal cytology and HR-HPV typing) increased the sensitivity in the groups evaluated and decreased specificity in some. Among HIV-infected MSM, the sensitivity of anal cytology alone to detect HSIL was 84.7%, whereas specificity was 30.0%. Although the sensitivity of the 2 tests combined (anal cytology and HR-HPV typing) to detect histologically confirmed HSIL increased (91.8%), the specificity decreased (22.0%). Overall, the sensitivity of cytology alone was higher in women compared to men and among PLWH compared to HIV-negative individuals.
Conclusion: While higher sensitivity for HSIL detection was seen for cytology alone for women and HIV-infected populations, co-testing increased the sensitivity for HSILs detection. Understanding the accuracy and cost of screening tools can guide interventions to broaden the availability of effective, low-cost screening options and promote anal cancer prevention. Access and availability of these tools in a wide context of communities must be considered.
Citation Format: Kandyce G. Keller, Celeste Leigh Pearce, Karen J. Ortiz-Ortiz, Jeslie M. Ramos-Cartagena, Humberto Guiot, Vivian Colón-López, Ashish A. Deshmukh, Maribel Tirado-Gómez, Ana Patricia Ortiz. Evaluating anal cancer screening approaches in high-risk populations in Puerto Rico [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 2241.