Screening men with HIV for anal cancer most cost-effective when initiated at age 35

Screening for anal cancer in men who have sex with men (MSM) and have HIV infection appears to be most cost-effective if started at age 35 years, according to a recent study.

Researchers developed a microsimulation model using data from the ANCHOR trial and other published literature to quantify the cost-effectiveness and benefits versus harms of different anal cancer screening strategies in MSM with HIV. The model tested different methods of screening and triage, different ages at which to begin screening (≥35 years, ≥40 years, or ≥45 years), and different screening intervals (annual, biennial, triennial, or quadrennial). The main outcome measures were incremental cost-effectiveness ratios (ICERs) of dollars per quality-adjusted life-year (QALY) and the tradeoff of harms (defined as high-resolution anoscopies) versus benefits (defined as cancer cases averted and life-years gained). The results were published June 17 by Annals of Internal Medicine.

The model estimated that without screening, 4,064 cases of anal cancer and 680 deaths would occur over the lifetime of 100,000 MSM with HIV who were 35 years of age or older. The researchers found that starting screening at age 35 years with cytology dominated starting at ages 40 and 45 years or older, with ICERs ranging from $87,731 for quadrennial screening to $350,100 for annual screening. The comparative analysis assessed strategies including quadrennial human papillomavirus (HPV) 16, quadrennial HPV 16/18, triennial HPV 16/18, triennial high-risk HPV, biennial HPV 16/18, biennial high-risk HPV, annual cytology with high-risk HPV triage, and annual high-risk HPV, with ICERs ranging from $81,341 to $2,510,847. Triage options offered the most efficient use of high-risk anoscopies in the harm-to-benefit analysis, while in the sensitivity analysis, ICERs decreased for those who were newly eligible for screening. For 35-year-old newly eligible MSM with HIV, ICERs for cytology ranged from $70,750 for quadrennial screening to $223,895 for annual screening.

Limitations of the study include that it assumed perfect adherence to screening, diagnosis, and follow-up, did not measure the effects of HPV vaccination, and cannot be generalized to other high-risk groups, the authors noted. They concluded that screening for anal cancer is cost-effective in MSM with HIV who are age 35 years and older, with more value in younger birth cohorts who are newly eligible for screening.

“In addition, cost-effectiveness and harm-to-benefit ratios varied across a wide range of intervals and approaches. These findings imply that value-based prioritization of anal cancer screening is needed to optimize screening use,” they wrote. “The findings of this study could inform screening guidelines, improve practices, reduce screening harms and enhance benefits, and optimally streamline the use of scarce screening resources.”