Does Screening With the Galleri Test in the NHS Reduce the Likelihood of a Late-stage Cancer Diagnosis in an Asymptomatic Population? A Randomised Clinical Trial

This is a prospective, randomized, controlled trial to assess the performance and clinical utility of a multi‐cancer early detection test for population screening in the UK when added to standard of care. Participants and the study teams remain blinded throughout the study with the exception of the study nurses returning the results and a small number of staff to enable them to perform administrative duties. Blinding is maintained for participants with the exception of those participants who test positive. Those who test positive will be informed by designated trial staff and will be referred for standard of care investigations and treatment. Trial sponsor employees, the CIs and site staff (unless identified differently in the blinding plan for study conduct needs) will remain blinded throughout the study. Randomization will be to either the intervention arm, with blood collection and evaluation of the test with consequent investigation and treatment of a positive test through referral to the NHS urgent two week wait pathway, or to the control arm, where blood samples are collected at designated intervals and will be stored for potential future evaluation, but participants do not receive test results and otherwise continue to receive routine NHS care. Unless diagnosed with cancer, participants in both arms will be asked to return for annual visits at approximately 12 and 24 months. All participants whether test positive, test negative or not tested will be followed for cancer and associated outcomes via NHS dataset linkages.