Is the outcome after hepatectomy for transitional hepatocholangiocarcinoma different from that of hepatocellular carcinoma and mass-forming cholangiocarcinoma? A case-matched analysis

Hepatocholangiocarcinoma (HCC-CC) is a rare malignancy containing features of both hepatocellular carcinoma (HCC) and mass-forming cholangiocarcinoma (MFCCC), of which the outcome after hepatectomy remains to be clarified. The aim of this study was to analyze the characteristics and outcomes of patients with transitional HCC-CC and compare them with those of patients with HCC and MFCCC. Our prospectively maintained database was queried, and 14 transitional HCC-CC patients were identified over a total of 406 consecutive hepatic resections. A 1:1:1 match was performed with HCC and MFCCC patients operated in the same period. A total of 42 patients were matched according to tumor stage (T1-2-3, N0, M0), number of tumors, R0 resection, no 90-day mortality, and follow-up. Primary endpoints were disease-free survival (DFS) and overall survival (OS). Disease-free survival rates at 1-, 3-, and 5-year were 71.4%, 57.1%, 35.7% for transitional HCC-CC patients; 85.7%, 40.4%, 10.1% for HCC patients; 85.1%, 34.0%, 22.7% for MFCCC patients (5-year DFS: HCC-CC vs. HCC, p = 0.575; HCC-CC vs. MFCCC, p = 0.766, respectively). Similarly, OS rates at 1-, 3-, and 5-year were 92.9%, 71.4%, 64.3% for transitional HCC-CC patients; 100%, 64.3%, 41.7% for HCC patients; 100%, 54.5%, 43.6% for MFCCC patients (5-year OS: HCC-CC vs. HCC, p = 0.891; HCC-CC vs. MFCCC, p = 0.673, respectively). When accurately matched with respect to tumor burden, transitional HCC-CC patients show similar outcomes to those of HCC and MFCCC patients. Further evaluations of differences in tumor biology are necessary to better characterize the prognosis of transitional HCC-CC patients.