EP140 - Cervical HPV16 as a marker of anal HPV16 misses a substantial proportion of patients at risk for anal dysplasia

Purpose/Background: Screening for and treating anal dysplasia among people living with HIV was shown to decrease anal cancer rates in the ANCHOR trial. Based on these findings, a preventative strategy has been recommended for populations with increased incidence of anal cancer compared to the general population. Group A high-risk factors (>10x increased incidence) include those living with HIV, men who have sex with men, transgender women, solid organ transplant recipients, and those with vulvar high-grade dysplasia or cancer. Group B moderate-risk patients (1-10x increased incidence) include those with persistent cervical HPV16 (cHPV), perianal warts, vaginal/cervical high-grade dysplasia or cancer, or medically immunosuppressed. Our colorectal surgery practice instituted a clinic-based high resolution anoscopy clinic and noticed cHPC and anal HPV16 (aHPV) infection did not always co-occur. The goal of this work was to evaluate for concordance of aHPV16 and cHPV16 toward understanding if persistent cHPV16 adequately reflects risk of aHPV16 infection.

Methods/Interventions: Under an IRB approved protocol at a tertiary academic center, anal cytology with HPV co-tests collected between 2019 and 2025 were evaluated. Inclusion criteria were tests from adults over 18 years old, biologic sex at birth female, and at least one aHPV16 positive test result. All other tests were excluded. Electronic medical records were evaluated for all cHPV and aHPV testing and the demographic characteristics of age at last test, race, ethnicity, BMI, and high- or moderate-risk factors for anal dysplasia.

Results/Outcomes: 47 patients had anal testing that was positive for HPV16. The average age was 54 +/-14 years, BMI 28 +/-6, 95% white. 26 (55%) had group A risk factors, 19 (40%) group B risk factors, and 2 (4%) had no risk factors for anal dysplasia screening. Patients had multiple cervical tests over an average of 2.6 +/- 1.9 years and multiple anal tests over an average of 1.9 +/-0.9 years. cHPV16 was positive in 33 (70%); among those who were not cHPV16+, nine were cHPV negative (19%) and five (11%) were cHPV18 or other high-risk serotype positive. Among those who were aHPV16+ but cHPV16-, 57% (8/14) had undergone anoscopy and all had dysplasia: 75% (6/8) had high grade intraepithelial neoplasia (HSIL) and 25% (2/8) had low grade intraepithelial neoplasia (LSIL) of the anus.

Conclusion/Discussion: Among biologic sex at birth female patients with aHPV16 infection, 30% do not have cHPV16 infection. Among those without cHPV16, the majority had anal HSIL found at anoscopy. Although limited in sample size, these data suggest that relying on cHPV16 infection as a marker of aHPV16 will miss a substantial number of patients at risk for HPV associated dysplasia.