Competing interests: The SUMMIT Study is funded by GRAIL. SMJ is a Wellcome Trust Senior Fellow in Clinical Science and supported by the Rosetrees Trust, UCLH Charitable Foundation and the Roy Castle Lung Cancer Foundation. This work was partially supported by the UCLH/UCL Department of Health’s NIHR Biomedical Research Centre’s funding scheme, the CRUK Lung Cancer Centre of Excellence and CRUK Early Detection Centre. AD declares personal fees from Boehringer Ingelheim, GlaxoSmithKline (GSK), Galapagos and Galecto. CH, JLD, ST and MR are funded or part-funded by GRAIL as part of the SUMMIT Study. AN declares that he is a member of the Advisory Board for Aidence, The Netherlands, and he is part-funded by the UCLH Biomedical Research Centre (BRC).