Combined hepatocellular cholangiocarcinoma: A population-based retrospective study.

e16291 Background: In 2011, the Ministry of Health, Labor and Welfare started providing data from the National Database of Health Insurance Claims and Specific Health Checkups of Japan (NDB) for research purposes. The NDB is an exhaustive and valuable database for health policymaking and research. It provides an accurate and most recent visualization of the burden of combined hepatocellular cholangiocarcinoma (CHC), a rare form of primary liver cancer, in Japan. In this study, we analyzed the CHC treatments and survival using data from the NDB. Methods: We retrospectively analyzed the NDB data to calculate the number of patients who were diagnosed with CHC (International Classification of Diseases, version 10 code of C22.7) and underwent treatment from 2016 to 2020. Results: Four hundred ten patients who were diagnosed as CHC and treated were identified. Of these patients, 82 patients (20.0%) underwent molecular targeted drugs (MTDs), 139 patients (33.9%) underwent transarterial chemoembolization/transarterial embolization (TACE/TAE), 150 patients (36.6%) underwent open liver resection (OLR) and 39 patients (9.5%) underwent laparoscopic liver resection (LLR). The median survival was 18 months for patients who underwent LLR, 23 months for patients who underwent OLR, 10 months for patients who underwent TACE/TAE, and 6 months for patients who underwent MTDs. Conclusions: This analysis of a national highly comprehensive database revealed the treatments performed for CHC and their prognosis. Liver resection was the most effective treatment compared with TACE/TAC and MTDs.