Multicentre cohort study to define and validate pathological assessment of response to neoadjuvant therapy in oesophagogastric adenocarcinoma by Noble, F, Lloyd, MA, Turkington, R, Griffiths, E, O'Donovan, M, O'Neill, JR, Mercer, S, Parsons, SL, Fitzgerald, RC, Underwood, TJ, Occams Consortium