Anal Dysplasia Screening in People Living with HIV: Long-Term Follow-Up in a Large Cohort from Northwest Spain.

Anal squamous cell carcinoma (SCC) is not a common disease in the general population, although its incidence is higher in people living with human immunodeficiency virus (PLWH). Anal SCC is caused by human papillomavirus (HPV) infection and arises from premalignant lesions termed squamous intraepithelial lesions (SILs). SIL surveillance programs are based on the early detection and treatment of SILs, especially those with a higher risk of transforming into cancer. An anal surveillance program has been under development in our institution since 2011. In this context, we performed a retrospective cohort study at the anal dysplasia unit of Álvaro-Cunqueiro Hospital (Spain). Epidemiological and clinical data were gathered from our Infectious Diseases Sample Collection (an open sample cohort including PLWH) from January 2011 to January 2022. A total of 493 PLWH were considered, 122 (24.7%) of whom were diagnosed with anal dysplasia at baseline, including 2 cases of anal SCC. Briefly, most of individuals were young men (median age, 38 years old) born in Spain (76%), whose vaccination rate before their inclusion in the program was scarce (<3%). Throughout the study period, 81 (16.4%) cases were diagnosed with high-grade squamous-intraepithelial lesions (HSILs) and 3 with anal SCC. At the baseline, severe immunosuppression (i.e., nadir CD4⁺ lymphocyte count below 200 cell/μL), and prior diagnosis of condyloma acuminata were more frequent within the group with SILs. Conversely, the baseline CD4⁺ lymphocyte count was similar among both groups. HPV-16 was related to a higher risk of HSILs (odds ratio: 2.76). At the end of the follow-up, 385 PLWH had been retained in care; one patient had died of anal cancer. Anal dysplasia was common (25% of cases), especially among patients infected by HPV-16, diagnosed with condyloma acuminata, and who were severely immunosuppressed. HPV-16 was the main risk factor for the presentation of HSILs.