Sustained Elevation of Postoperative Serum Level of Carbohydrate Antigen 19-9 is High-Risk Stigmata for Primary Hepatic Recurrence in Patients with Curatively Resected Pancreatic Adenocarcinoma

Background Survival after surgery for pancreatic adenocarcinoma (PA) is poor and heterogeneous, even for curative (R0) resection. Serum carbohydrate antigen (CA) 19-9 levels are important prognostic markers for resected PA. However, sustained elevation of CA19-9 in association with the patterns of recurrence has been rarely investigated. Methods Patients who underwent R0 resection ( n = 539) were grouped according to postoperative serum CA19-9 levels (Group E: sustained elevation; Group N: no elevation). Clinicopathological factors, patterns of recurrence, and survival were compared between the groups. Results Group E ( n = 159) had significantly shorter median overall survival (17.1 vs. 35.4 months, p < 0.0001) than Group N ( n = 380). Postoperative CA19-9 elevation was a significant independent predictor of poor survival in multivariate analysis (hazard ratio 1.98, p < 0.0001). The rate of hepatic recurrence in Group E was 2.6-fold higher than in Group N (45% vs. 17%, p < 0.0001). Postoperative CA19-9 elevation was a strongest independent predictor of primary hepatic recurrence ( p < 0.0001) by a multiple regression model. Loco-regional, peritoneal, and other distant recurrence did not differ between the groups. The extent of preoperative CA19-9 elevation was correlated sustained elevation of CA19-9 after surgery ( p < 0.0001) and primary hepatic recurrence ( p = 0.0019). Conclusions Sustained CA19-9 elevation was strong predictor of primary hepatic recurrence and short survival in cases of R0 resection for PA.