Preoperative evaluation of pancreatic ductal adenocarcinoma with synchronous liver metastasis: Diagnosis and assessment of unresectability

AIM: To identify predictors for synchronous liver metastasis from resectable pancreatic ductal adenocarcinoma (PDAC) and assess unresectability of synchronous liver metastasis. METHODS: Retrospective records of PDAC patients with synchronous liver metastasis who underwent simultaneous resections of primary PDAC and synchronous liver metastasis, or palliative surgical bypass, were collected from 2007 to 2015. A series of pre-operative clinical parameters, including tumor markers and inflammation-based indices, were analyzed by logistic regression to figure out predictive factors and assess unresectability of synchronous liver metastasis. Cox regression was used to identify prognostic factors in liver-metastasized PDAC patients after surgery, with intention to validate their conformance to the indications of simultaneous resections and palliative surgical bypass. Survival of patients from different groups were analyzed by the Kaplan-Meier method. Intra- and post-operative courses were compared, including complications. PDAC patients with no distant metastases who underwent curative resection served as the control group. RESULTS: CA125 > 38 U/mL (OR = 12.397, 95%CI: 5.468-28.105, P < 0.001) and diabetes mellitus (OR = 3.343, 95%CI: 1.539-7.262, P = 0.002) independently predicted synchronous liver metastasis from resectable PDAC. CA125 > 62 U/mL (OR = 5.181, 95%CI: 1.612-16.665, P = 0.006) and age > 62 years (OR = 3.921, 95%CI: 1.217-12.632, P = 0.022) correlated with unresectability of synchronous liver metastasis, both of which also indicated a worse long-term outcome of liver-metastasized PDAC patients after surgery. After the simultaneous resections, patients with post-operatively elevated serum CA125 levels had shorter survival than those with post-operatively reduced serum CA125 levels (7.7 mo vs 16.3 mo, P = 0.013). The survival of liver-metastasized PDAC patients who underwent the simultaneous resections was similar to that of non-metastasized PDAC patients who underwent curative pancreatectomy alone (7.0 mo vs 16.9 mo, P < 0.001), with no higher rates of either pancreatic fistula (P = 0.072) or other complications (P = 0.230) and no greater impacts on length of hospital stay (P = 0.602) or post-operative diabetic control (P = 0.479). CONCLUSION: The criterion set up by CA125 levels could facilitate careful diagnosis of synchronous liver metastases from PDAC, and prudent selection of appropriate patients for the simultaneous resections.