Acute Upper Gastrointestinal Bleeding is Associated With Poor Prognosis in Patients With Biliary Tract Cancer. - Schumacher, Jan Christoph; Lang, Sonja; Kasper, Philipp; Martin, Anna; Waldschmidt, Dirk; Bürger, Martin; Töx, Ulrich; Neumann‐Haefelin, Christoph; Allo, Gabriel (Cancer Medicine, 2026)