Men who have sex with men living with HIV (MSM LWH) are at highest risk for human papillomavirus (HPV)-associated anal cancer. There is no consensus on the optimal screening initiation age. This study aimed to assess the prevalence and severity of anal HPV disease among MSM LWH under the age of 35, which is a currently proposed screening age threshold. Between 2014 and 2020, 1255 18-to-34-year-old MSM LWH underwent anal cytology screening. 916 were co-tested for high-risk HPV (HR-HPV). 467 underwent high-resolution anoscopy (HRA) and biopsy. Cancer registry data were queried. Predictors of abnormal cytology (ie, ≥ASCUS) and histological high-grade squamous intraepithelial lesions (HSIL) were evaluated using unadjusted logistic regression models. Median age was 28 years (range, 18-34). 19% received at least one dose of HPV vaccine. Abnormal cytology rate was 65%. HR-HPV and HPV16 prevalence were 87% and 30%. Biopsy results were benign (10%), LSIL (43%) and HSIL (47%). No cases of prevalent or incident anal cancers were detected. Findings were similar between age subgroups (18-24, 25-29 and 30-34) except for a higher prevalence of AIN 3 in the 30-34 group (19%). Abnormal cytology was significantly associated with HR-HPV infection. Histological HSIL was associated with HR-HPV infection and cytological LSIL or worse. The absence of anal cancer in a large cohort of MSM LWH under the age of 35, despite high prevalence of anal HR-HPV infection and precancer, supports an age-based anal cancer screening strategy for MSM LWH. 根据研究，与人类乳头瘤病毒（HPV）相关的肛门癌最易发生在同性性行为男性艾滋病毒感染者（MSM LWH）身上。目前尚无关于最佳筛查起始年龄的共识。本研究旨在评估35岁以下MSM LWH群体中肛门HPV疾病的患病率和严重程度，这是目前提出的筛查年龄门槛。2014年至2020年间，1255名年龄在18至34岁之间的MSM LWH接受了肛门细胞学筛查。其中，916人进行了高危HPV（HR-HPV）联合检测，467人进行了高分辨率肛门镜检查（HRA）和活检。同时，查询了癌症登记数据。通过未经调整的逻辑回归模型评估异常细胞学结果（即≥ASCUS）和组织学高级别鳞状上皮内病变（HSIL）的预测因素。中位年龄为28岁（范围为18-34岁）。19%的人接种了至少一剂HPV疫苗。异常细胞学率为65%。HR-HPV和HPV16的流行率分别为87%和30%。活检结果为良性（10%）、低级别鳞状上皮内病变（LSIL）（43%）和高级别鳞状上皮内病变（HSIL）（47%）。未发现肛门癌的现有或新发病例。在不同年龄子组（18-24岁、25-29岁和30-34岁）间，发现相似结果，除了30-34岁组AIN 3的患病率较高（19%）。异常细胞学结果与HR-HPV感染密切相关。组织学HSIL与HR-HPV感染以及细胞学LSIL或更严重病变相关。尽管肛门HR-HPV感染和癌前病变高发，但未发现在35岁以下大型MSM LWH群体中存在肛门癌的病例，这支持了基于年龄的肛门癌筛查策略用于MSM LWH。 © 2023 UICC.

Men who have sex with men living with HIV (MSM LWH) are at highest risk for human papillomavirus (HPV)-associated anal cancer. There is no consensus on the optimal screening initiation age. This study aimed to assess the prevalence and severity of anal HPV disease among MSM LWH under the age of 35, which is a currently proposed screening age threshold. Between 2014 and 2020, 1255 18-to-34-year-old MSM LWH underwent anal cytology screening. 916 were co-tested for high-risk HPV (HR-HPV). 467 underwent high-resolution anoscopy (HRA) and biopsy. Cancer registry data were queried. Predictors of abnormal cytology (ie, ≥ASCUS) and histological high-grade squamous intraepithelial lesions (HSIL) were evaluated using unadjusted logistic regression models. Median age was 28 years (range, 18-34). 19% received at least one dose of HPV vaccine. Abnormal cytology rate was 65%. HR-HPV and HPV16 prevalence were 87% and 30%. Biopsy results were benign (10%), LSIL (43%) and HSIL (47%). No cases of prevalent or incident anal cancers were detected. Findings were similar between age subgroups (18-24, 25-29 and 30-34) except for a higher prevalence of AIN 3 in the 30-34 group (19%). Abnormal cytology was significantly associated with HR-HPV infection. Histological HSIL was associated with HR-HPV infection and cytological LSIL or worse. The absence of anal cancer in a large cohort of MSM LWH under the age of 35, despite high prevalence of anal HR-HPV infection and precancer, supports an age-based anal cancer screening strategy for MSM LWH.© 2023 UICC.