OC-0631 Proton and photon treatment planning comparison for oesophageal cancer between six European centres. (August 2021) - Hoffmann, L.; Mortensen, H.; Berbee, M.; Bizzocchi, N.; Bütof, R.; Canters, R.; Defraene, G.; Ehmsen, M.L.; Freixas, G.V.; Haustermans, K.; Korevaar, E.W.; Makocki, S.; et al.