Hepatocellular-Cholangiocarcinoma Collision Tumors: An Update of Current Management Practices.

Combined hepatocellular-cholangiocarcinoma (cHCC-CC) is a rare form of primary hepatic collision tumor, with an incidence ranging from 0.4 to 14.2%. Given the diagnostic challenges and lack of randomized trials, standardized treatment has yet to be established. We aim to review the literature to summarize the diagnosis, molecular characteristics, current treatment modalities, and challenges for cHCC-CC. A literature review was performed using PubMed. We included studies investigating and describing cHCC-CC, focusing on surgical, medical, and radiologic treatments. Overall prognosis is poor, with a 5-year survival rate under 30%. Minor or major hepatectomy with R0 resection is the only curative treatment; however, recurrence is likely (as high as 50% within 5 years). The role of liver transplantation is also highly debated given the biliary nature of these tumors, with cHCC-CC as a relative contraindication for liver transplantation. Although gemcitabine-based treatments had higher progression-free survival over sorafenib, there is no standard chemotherapy regimen. Treatment with gemcitabine and platinum demonstrates improved disease control rates compared to gemcitabine in conjunction with 5-fluorouracil (78.4% verse 38.5% respectively). Additionally, platinum-containing chemotherapy regimens exhibit a higher overall response rate than non-platinum regimens (21.4% verse 7.0% respectively). These molecular-directed therapies have prolonged survival for HCC, but further investigation needs to be done to assess their utility in patients with cHCC-CC. cHCC-CC is a rare and complex subset of primary hepatic neoplasms with a dismal prognosis and unstandardized treatment options. Further trials need to be performed to investigate systemic chemotherapy and immunotherapy options for patients with unresectable disease.