Anal cancer screening starting at age 35 years could be cost-effective and clinically beneficial among men who have sex with men living with human immunodeficiency virus, according to a modeling study.
The research assessed multiple screening methods and intervals to guide screening recommendations in this high-risk population.
Using a microsimulation model, investigators evaluated 52 screening strategies, including cytology, high-risk human papillomavirus (hrHPV) testing, HPV genotyping, cotesting, and triage options. Each approach was analyzed across starting ages (35, 40, or 45 years) and screening intervals (annual, biennial, triennial, and quadrennial). Researchers estimated cancer incidence, mortality, cost-effectiveness, and harm-to-benefit tradeoffs.
Without screening, the model projected 4,064 anal cancer cases and 680 deaths over the lifetime of 100,000 men who have sex with men (MSM) with human immunodeficiency virus (HIV) aged 35 years or older. Screening initiated at 35 years consistently prevented more cancer cases and deaths compared with later starting ages. Cytology screening alone showed incremental cost-effectiveness ratios (ICER) ranging from $87,731 per quality-adjusted life-year (QALY) gained for quadrennial screening to $350,100 for annual screening.
Several strategies were identified on the cost-effectiveness frontier, including quadrennial HPV16 genotyping (ICER = $81,341), quadrennial HPV16/18 ($81,377), triennial HPV16/18 ($148,965), triennial hrHPV ($187,476), biennial HPV16/18 ($229,460), biennial hrHPV ($234,264), annual cytology with hrHPV triage ($406,569), and annual hrHPV alone ($2.5 million).
The researchers also examined harm-to-benefit ratios based on high-resolution anoscopies (HRAs) per life-year gained. Quadrennial cytology with HPV16 triage required 61 HRAs per life-year gained, whereas annual hrHPV alone required 1,210 HRAs. More frequent screening led to higher HRA use with limited additional benefit.
For newly eligible MSM with HIV aged 35 years, screening yielded even lower ICERs of $70,750 for quadrennial cytology, $103,800 for triennial cytology, $126,776 for biennial cytology, and $223,895 for annual cytology. Delaying screening to age 40 or 45 increased costs and reduced cancer prevention.
The model incorporated natural history data on HIV, HPV infection, high-grade squamous intraepithelial lesions , and anal cancer using information from the ANCHOR trial and U.S. epidemiologic studies. The researchers assumed full adherence to screening, diagnosis, and treatment, and validated the model against U.S. population data.
Anal cancer risk was elevated in MSM with HIV, with an incidence of 85 per 100,000, approximately 45 times higher compared with in men without HIV. Most cases were linked to persistent hrHPV infection, primarily HPV16.
The researchers concluded that value-based prioritization may optimize screening use and resource allocation. While cytology remains widely used, less frequent HPV-based strategies may reduce unnecessary procedures while maintaining clinical benefits.
The research was supported by the National Cancer Institute.
Source: Annals of Internal Medicine
