Background: Pancreatic ductal adenocarcinoma (PDAC) is known to have a poor prognosis, early local invasion, and distant metastasis. Surgical resection is the most effective treatment, and tumor recurrence can be the key factor affecting the surgical outcome. Serum carbohydrate antigen 19-9 (CA19-9) is a tumor marker with high sensitivity to pancreatic cancer; elevated CA19-9 levels often indicate poor biological behavior. Tumor size is also a crucial factor that affects the prognosis. Therefore, we developed a program to evaluate the effect of the ratio of CA19-9 to total tumor volume (CA19-9/TTV) as a prognostic marker on tumor recurrence and long-term survival in patients with PDAC following pancreaticoduodenectomy (PD). Methods: Data from 200 patients who underwent PD for PDAC were retrospectively analyzed. CA19-9/TTV was calculated according to preoperative CA19-9 and TTV, and patients were divided into two groups according to the optimal cut-off value. Univariate and multivariate analyses were performed on the clinicopathological data to screen the risk factors affecting postoperative recurrence and long-term prognosis of patients with PDAC undergoing PD. Results: The receiver operating characteristic curve showed that the best cut-off value was 5.62 (area under curve [AUC], 0.633; 95% CI: 0.548-0.718). Multivariate analysis showed that tumor differentiation and CA19-9/TTV were independent risk factors for the long-term prognosis of PDAC (P = 0.004, P = 0.007), as well as for tumor recurrence (P = 0.008, P = 0.008). Conclusion: CA19-9/TTV is an independent risk factor for the prognosis of PDAC and may be a new marker for lower survival benefits.
Keywords: Pancreatic carcinoma; carbohydrate antigen 19-9; pancreaticoduodenectomy; prognosis; total tumor volume.