Surgery of gastric cancer and esophageal cancer: does age matter? - Nienhüser, Henrik; Skusa, Romy; Peters, Leila; Blank, Susanne; Strowitzki, Moritz; Bruckner, Thomas; Jäger, Dirk; Weichert, Wilko; Ulrich, Alexis; Büchler, Markus W.; Schmidt, Thomas (Journal of surgical oncology, 2015)