1. From Cambridge University Hospitals NHS Foundation Trust, Cambridge (M.S.G.), the Department of Surgery and Cancer (M.S.G., F.H., A.H.D.) and Imperial Clinical Trials Unit (X.L., J.W.), Imperial College London, London, University of Birmingham, Birmingham (A.B.), Gloucestershire Hospitals NHS Foundation Trust, Gloucester (R.B., K.R.P.), the Medical Research Council Population Health Research Unit and the Clinical Trial Service Unit and Epidemiological Studies Unit, Nuffield Department of Population...