Anal cancer screening cost-effective for men who have sex with men with human immunodeficiency virus aged above 35 years

1. In this microsimulation model, initiation of anal cancer screening in men who have sex with men with human immunodeficiency virus at age 35 was cost-effective and greatly reduced mortality.

2. Most cost-efficient strategies utilized cytology and human papillomavirus (HPV)-based triage approaches, with quadrennial cytology with HPV16 triage being associated with the least harm.

Evidence Rating Level: 2 (Good)

Study Rundown: Although anal cancer is rare in the general population, people with HIV, particularly men who have sex with men (MSM), have a significantly higher risk. While many organizations have released consensus guidelines recommending screening in this population, there is limited data regarding costs and long-term outcomes of screening. This study aimed to determine the cost-effectiveness, benefits, and harms of anal cancer screening among MSM with HIV. An initial base-case analysis showed that cytology alone would greatly reduce the number of cases and deaths from anal cancer, particularly with younger age at screening and more frequent screens. However, the relative incremental cost-effectiveness ratios (ICERs) increased with higher screening frequencies. Over fifty unique screening strategies were analyzed, and mortality reductions ranged between one-quarter and nearly two-thirds. Of the most cost-effective strategies, quadrennial cytology with HPV16 triage resulted in the least harm, as measured by number of high-resolution anoscopies (HRAs) per life-year gained. The generalizability of this study was limited by its assumption of perfect adherence to screening, diagnosis, and follow-up treatments; an inability to measure the effect of HPV vaccination; and an inability to capture the heterogeneity of anal cancer risk among people with HIV. Nevertheless, this study suggested that anal cancer screening among MSM with HIV had high value particularly among younger individuals who are newly eligible for screening, although value-based prioritization may remain important to reduce harms.

Click to read the study in AIM

Relevant Reading: Recommendations Favoring Anal Cytology as a Method for Anal Cancer Screening: A Systematic Review

In-Depth [prospective cohort study]: This microsimulation model aimed to determine the cost-effectiveness and benefits or harms of anal cancer screening among MSM with HIV aged 35 years or above. Key outcomes, including anal detection of high-grade squamous intraepithelial lesions (HSILs), incidence and mortality of anal cancer, quality-adjusted life expectancy, use of HRAs, and cost-effectiveness, were determined by simulating various primary screening scenarios and triage follow-up options. Progression to anal cancer and regression of HSIL were based on data from the ANCHOR (Anal Cancer-HSIL Outcomes Research) trial and determined using age and AIDS status. Screening for HSILs was done using anal cytology, hrHPV testing, and simultaneous testing of cytology and HPV; screening was considered for individuals aged 35 years or above, 40 years or above, or 45 years or above, as well as annually, biennially, triennially, and quadrennially. The base-case analysis showed that no screening would lead to an estimated 4064 anal cancer cases and 680 anal cancer deaths per every 100,000 MSM with HIV aged 35 years and above, with even cytology alone demonstrating substantial benefit. A further 52 unique screening strategies each reduced anal cancer mortality, ranging from 25.8% for quadrennial cytology with HPV16 triage to 63.1% for annual cytology with hrHPV co-testing. Among the 8 most cost-effective strategies, quadrennial cytology with HPV16 triage resulted in the least harm, yielding 61 HRAs per life-year gained. Initiating screening at 35 years led to lower ICERs compared with population-wide screening regardless of screening frequency. Overall, this study suggested that anal cancer screening may be cost-effective at large, especially when initiating screening at 35 years, although there was substantial variation in benefits and harms between strategies.

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