The authors reply: Re: Yamamoto R, Sugiura T, Ashida R, Ohgi K, Yamada M, Otsuka S, and Uesaka K. Prognostic value of carbohydrate antigen 19-9 and the surgical margin in extrahepatic Cholangiocarcinoma. Ann Gastroenterol Surg. 2022;6:307-315. - Yamamoto R; Sugiura T; Ashida R; Ohgi K; Yamada M; Otsuka S; Uesaka K (Annals of gastroenterological surgery, 2023)