Multi-cancer early detection tests for general population screening: a systematic literature review.

Background: General population cancer screening in the United Kingdom is limited to selected cancers. Blood-based multi-cancer early detection tests aim to detect potential cancer signals from multiple cancers in the blood. The use of a multi-cancer early detection test for population screening requires a high specificity and a reasonable sensitivity to detect early-stage disease so that the benefits of earlier diagnosis and treatment can be realised. Objective: To undertake a systematic literature review of the clinical effectiveness evidence on blood-based multi-cancer early detection tests for screening. Methods: Comprehensive searches of electronic databases (including MEDLINE and EMBASE) and trial registers were undertaken in September 2023 to identify published and unpublished studies of multi-cancer early detection tests. Test manufacturer websites and reference lists of included studies and pertinent reviews were checked for additional studies. The target population was individuals aged 50-79 years without clinical suspicion of cancer. Outcomes of interest included test accuracy, number and proportion of cancers detected (by site and stage), time to diagnostic resolution, mortality, potential harms, health-related quality of life, acceptability and satisfaction. The risk of bias was assessed using the quality assessment of diagnostic accuracy studies-2 checklist. Results were summarised using narrative synthesis. Stakeholders contributed to protocol development, report drafting and interpretation of review findings. Results: Over 8000 records were identified. Thirty-six studies met the inclusion criteria: 1 ongoing randomised controlled trial, 13 completed cohort studies, 17 completed case-control studies and 5 ongoing cohort or case-control studies. Individual tests claimed to detect from 3 to over 50 different types of cancer. Diagnostic accuracy of currently available multi-cancer early detection tests varied substantially: Galleri Limitations: Study selection was complex; it was often difficult to determine the stage of development of multi-cancer early detection tests. The evidence was limited; there were no completed randomised controlled trials and most included studies had a high overall risk of bias, primarily owing to limited follow-up of participants with negative test results. Only one study of Galleri recruited asymptomatic individuals aged over 50 in the United States of America; however, study results may not be representative of the United Kingdom's general screening population. No meaningful results were reported relating to patient-relevant outcomes, such as mortality, potential harms, health-related quality of life, acceptability or satisfaction. Conclusions: All currently available multi-cancer early-detection tests reported high specificity (> 96%). Sensitivity was highly variable and influenced by study design, population, reference standard test used and length of follow-up. Future work: Further research should report patient-relevant outcomes and consider patient and service impacts. Study registration: This study is registered as PROSPERO CRD42023467901. Funding: This award was funded by the National Institute for Health and Care Research (NIHR) Health Technology Assessment programme (NIHR award ref: NIHR161758) and is published in full in