What are current screening recommendations for anal cancer in high‑risk groups such as HIV‑positive men who have sex with men?
Executive summary
New consensus and federal guidance now recommend targeted anal cancer screening for people with HIV, with men who have sex with men (MSM) and transgender women living with HIV offered lab‑based screening from age 35 and other people with HIV from age 45; annual symptom review and a digital ano‑rectal exam (DARE) are advised for eligible groups, and abnormal cytology or symptoms should prompt referral for high‑resolution anoscopy (HRA) when available [1] [2] [3]. The recommendations rest on recent trial and modeling data showing that treating high‑grade squamous intraepithelial lesions (HSIL) reduces progression to invasive anal cancer and that targeted screening is cost‑effective in the highest‑risk populations, while acknowledging gaps in definitive trial evidence for some subgroups and practical limits in HRA availability [4] [5] [6].
1. Who should be screened and when: a risk‑stratified threshold
The International Anal Neoplasia Society and subsequent U.S. panel conclude that MSM and transgender women with HIV should begin routine anal cytology‑based screening at age 35 because their anal cancer incidence exceeds the risk threshold warranting screening; other people with HIV should begin at age 45, with some higher‑risk individuals (history of cervical/vulvar HSIL, transplant recipients) considered earlier or by shared decision‑making [1] [7] [8].
2. What the screening program should include: exams, swabs, and HRA referral
Guidelines recommend an annual assessment for anal symptoms and a DARE for all people with HIV in the eligible age groups, plus lab‑based collection of anorectal specimens (anal cytology and/or high‑risk HPV testing) to detect HSIL, with any abnormal results, suspicious symptoms or DARE findings triggering referral for HRA for diagnostic evaluation and possible treatment [2] [3] [9].
3. Tests and algorithms: cytology, hr‑HPV, co‑testing and triage options
Multiple strategies exist: anal cytology alone, hr‑HPV testing alone, co‑testing, and two‑step approaches have been modeled; co‑testing or hr‑HPV‑based algorithms tend to increase sensitivity for HSIL and reduce missed lesions, and recent guidelines outline several acceptable strategies tailored to resource settings and risk groups [6] [10] [11].
4. Evidence base and why recommendations shifted now
The recommendations follow the ANCHOR trial and large cohort analyses showing that detecting and treating anal HSIL in people with HIV reduces progression to anal cancer and that targeted screening in MSM with HIV is cost‑effective; these data prompted U.S. federal guidance endorsing screening programs for high‑risk people with HIV [5] [4] [3].
5. Pragmatic caveats: access, resource constraints and uncertainty
Guideline authors and major centers note that HRA capacity is limited; where HRA is unavailable, annual rectal exam and referral for standard anoscopy if screening is positive is advised, and the value of screening younger asymptomatic persons remains uncertain pending further research [9] [3] [2]. Systematic reviews from earlier years also highlighted that evidence for the optimal frequency and for DARE’s standalone efficacy is limited and often based on expert opinion [12].
6. Harms, costs and equity considerations
Anal cytology screening, HRA and treatment of HSIL carry potential harms (procedural morbidity, overdiagnosis, anxiety) and resource costs; economic analyses model screening as cost‑effective in MSM with HIV at age 35 and older but recommend value‑based prioritization and attention to equitable HRA access to avoid exacerbating disparities [4] [13].
7. Bottom line and practical pathway
For HIV‑positive MSM and transgender women, begin annual symptom review, DARE and lab‑based anorectal screening at 35 with HRA referral for abnormalities; for other people with HIV, begin similar assessment and screening at 45, with flexibility for earlier evaluation in those with additional risks or symptoms and pragmatic fallback to standard anoscopy where HRA is unavailable [1] [2] [9].