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.