Nivolumab versus chemotherapy in patients with advanced oesophageal squamous cell carcinoma refractory or intolerant to previous chemotherapy (ATTRACTION-3): a multicentre, randomised, open-label, phase 3 trial Ioannis Xynos , Mamoru Kodani , Yuko Kitagawa +15 more 2019 The Lancet Oncology 1165 citations