Abstract 1267: Projected impact of liquid biopsy screening strategies with high sensitivity in focused populations and high specificity in broad populations

Abstract Purpose: Two 'liquid biopsy' cancer screening approaches exist: Focused and Broad. The Focused approach targets specific cancers and populations lacking adequate screening, emphasizing high sensitivity. The Broad approach aims to detect various cancers in the population, prioritizing high specificity to minimize false-positives but potentially compromising sensitivity. The public health impact and testing burden of these approaches remain unexplored. Methods: Projected cancer mortality reduction and annual test volumes are based on published data for liquid biopsy tests. Focused screening is modeled for patients not undergoing guideline-recommended screening for lung, liver, and colorectal cancers. Broad screening is modeled for individuals aged 50-80, assuming the detection of all cancer types. Averted deaths are calculated by combining published mortality reduction estimates or assumed at 20% if not available. Reductions are adjusted for reported test sensitivities. Liquid biopsy cannot prevent deaths from cancers recommended for screening if the person has already undergone the recommended test. Results: Focused and broad screening strategies annually prevented around 20,000 cancer deaths. Focused screening necessitated testing only one-fifth of the people compared to broad screening (30MM vs. 150MM). The projected reduction in mortality for focused testing relied entirely on randomized studies, while the equivalent statistic for the broad strategy was 53%. Conclusions: Equivalent reductions in cancer deaths can be achieved with focused screening at high sensitivity and broad screening at high specificity, with only one-fifth of the testing burden. The influence of false positives in focused testing and false reassurance in broad testing may impact these findings, which could also be influenced by testing and follow-up costs. Table 1 Annual cancer deaths averted (thousands) Focused cancer testing Broad cancer testing Lung 10-12 4-8 Liver 4-5 1 Colorectal 3-4 1 Other screened cancers* Not modeled 1-2 Unscreened cancers Not modeled 6-10 Total 17-20 14-22 Annual test volume (millions) 30 150 *Other screened cancers includes prostate, breast, cervical. Range reflects the application of reported Stage I or overall sensitivity, respectively. Citation Format: Peter B. Bach, Niti U. Trivedi, Lindsey Cotton. Projected impact of liquid biopsy screening strategies with high sensitivity in focused populations and high specificity in broad populations [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 1267.