Anal cancer is a major source of cancer morbidity for people living with HIV (PWH). Evolving guidelines recommend initiating anal cancer screening for PWH at age 35. With emerging evidence supporting the cancer prevention benefits of anal high-grade squamous intraepithelial lesion (HSIL) treatment, we sought to analyze outcomes of anal dysplasia screening for PWH < 35 years.
Between January 2014 and August 2020, we identified initial anal cytology and high-risk HPV (hrHPV) test results for all PWH < 35 years who underwent screening in our health system. We then collected information on subsequent high-resolution anoscopy (HRA)-guided biopsies and linked cancer registry entries (to identify any anal cancer diagnoses) for this cohort. Using these data we compared screening and HRA outcomes according to demographics, CD4 count, HPV vaccination status and age subgroups.
1,389 PWH < 35 underwent anal dysplasia screening during the study period. Most (>90%) were 25-34 years of age and the vast majority were men (93%) of whom 98% were men who have sex with men. Only 28% received at least one dose of HPV vaccine before their initial screening cytology. Most subjects (66%) had cytologic abnormalities of ASCUS or greater (11% had HSIL cytology). 75% of cytology samples were co-tested for hrHPV with 85% of tests positive for any hrHPV type and 43% positive for HPV 16 and/or 18. Of subjects with abnormal screening cytology 62% underwent subsequent HRA which yielded anal HSIL in 44%. Among PWH who underwent HRA women had substantially less histologic HSIL than men (18% versus 42%; p=0.002). There was no significant difference in the proportion of persons diagnosed with histologic HSIL by age subgroup (<25, 25-29, 30-34; p=0.7). CD4 count at initial screen was not associated with severity of cytologic abnormalities, hrHPV infection or HSIL diagnosis. History of HPV vaccination was associated with lower rates of HPV 16/18 infection (38% in vaccinated versus 45% in unvaccinated, p=0.02) but did not impact rates of overall hrHPV infections or eventual HSIL diagnoses. No incident cancers were diagnosed during the follow-up period.
High-risk HPV infection, cytologic abnormalities, and associated histologic HSIL were all common in PWH under age 35. With emerging evidence regarding the benefits of anal HSIL treatment, the role of screening should be further investigated in this population.