From the Department of Oncology, University College London NHS Foundation Trust, 250 Euston Road, London NW1 2PG, England (M.K.); Paul Strickland Scanner Centre (A.R.P., A.G.) and Breast Cancer Research Unit (P.O., S.S., D.M., A. Makris), Mount Vernon Cancer Centre, Northwood, Middlesex, England; Department of Clinical Oncology, the Christie NHS Foundation Trust, Manchester, England (D.W.); Astra Zeneca UK Limited, Cambridge, England (M.L.A.); the Royal Marsden Hospital, Sutton, Surrey, England (J.N., D.M.K.); and Warwick Clinical Trials Unit, University of Warwick, Coventry, England (A. Marshall, J.D.).