Prognostic Value of Carbohydrate Antigen 19‐9 and the Surgical Margin in Extrahepatic Cholangiocarcinoma

AIM: The prognostic value of the perioperative carbohydrate antigen 19‐9 (CA19‐9) value and the prognostic relationship between the CA19‐9 value and the surgical margin in extrahepatic cholangiocarcinoma (EHCC) have not been fully discussed. METHODS: A total of 390 patients who underwent curative resection for EHCC between 2002 and 2018 were retrospectively analyzed. According to the perioperative CA19‐9 value, patients were divided into three groups: preoperative normal (Normal, n = 178), preoperative high and postoperative normal (Normalization, n = 155), and preoperative high and postoperative high (Nonnormalization, n = 57). Survival was analyzed according to the perioperative CA19‐9 value and surgical margin. RESULTS: The optimal cutoff value of CA19‐9 was 37 U/mL. Overall survival (OS) was significantly stratified according to the perioperative CA19‐9 value. The 5‐y OS rates in the Normal, Normalization, and Nonnormalization groups were 53%, 38%, and 23%, respectively (P < .001). Although the locoregional recurrence rate was comparable among the groups, the Normal group exhibited distant recurrence less frequently in comparison to the other groups. In the Normal group, the margin status had a significant impact on the OS (surgical resection with a negative margin [R0], 59% vs a microscopically positive margin [R1], 7% at 5‐y, P < .001). In contrast, in the Normalization and Nonnormalization groups, the OS rate of the R0 and R1 resection groups did not differ to a statistically significant extent. CONCLUSION: The perioperative CA19‐9 value was related to the prognosis of resectable EHCC. A preoperative CA19‐9 value of ≥37 U/mL reflected systemic disease. R0 resection did not affect the survival in this patient group.