Meta-analysis of prognostic factors for overall survival and disease-free survival among resected patients with combined hepatocellular carcinoma and cholangiocarcinoma

Background: Combined hepatocellular carcinoma and cholangiocarcinoma (CHCC-CC) is a rare subtype of primary liver malignancy and has been treated equally as intra-hepatic cholangiocarcinoma (IHCC) according to the 8th AJCC staging system. Owing to its rarity, its prognostic factors have been rarely explored and defined.Methods: PubMed, EMBASE, the Cochrane Library and Web of Science were searched up till January 1st, 2023 and eligible studies were restricted to studies reported prognostic factors of resected CHCC-CC. Standard Parmar modifications were used to determine pooled univariable hazard ratios (HRs).Results: A total of eleven studies with 1286 patients with resected classical CHCC-CC were finally included. Pooled results indicated that serum tumor biomarkers, including AFP, CA199, and CEA, were prognostic factors for postoperative overall survival (OS) and disease-free survival (DFS). Moreover, liver cirrhosis (P = 0.010), HBV infection (P = 0.030), and HCV infection (P < 0.001) were prognostic factors for OS. Age (HR = 1.03, P = 0.005) was a prognostic factor for DFS. Tumor size (OS: HR = 2, P < 0.001, DFS: HR = 2.15, P < 0.001), tumor number (OS: HR = 2.05, P < 0.001; DFS: HR = 1.96, P = 0.006), surgical margin (OS: HR = 2.33, <0.001001; DFS: HR = 2.35, P < 0.001), node metastasis (OS: HR = 2.96, P < 0.001; DFS: HR = 2.1, P < 0.001), vascular invasion (OS: HR = 2.17, P < 0.001; DFS: HR = 2.64, P < 0.001), and postoperative prophylactic trans-arterial chemotherapy embolization (PPTACE) (OS: HR = 1.67, P = 0.04; DFS: HR = 2.31, P < 0.001) were common prognostic factors for OS and DFS.Conclusion: Various risk factors unmentioned in the 8th AJCC staging system were identified. These promising findings would facilitate a more personalized predictive model and help clinicians to stratify patients with different survival outcomes.