Investigation of a Tumor Location-Specific Therapeutic Strategy for Intrahepatic Cholangiocarcinoma.

Objective: An optimal therapeutic strategy for intrahepatic cholangiocarcinoma (ICC) has not yet been determined. Herein we focused on intrahepatic tumor location and retrospectively analyzed tumor characteristics depending on location to elucidate a location-specific therapeutic strategy for ICC. Methods: Sixty-five ICC patients were divided into three groups based on the distance between the innermost portion of the tumor and portal vein branches observed on preoperative imaging: peripheral, intermediate and central ICC. Results: Median disease-specific survival (DSS) of the peripheral ICC was not reached, whereas median DSS was 32.9 months in intermediate ICC and 25.2 months in central ICC (p <0.05). Vascular invasion was observed in all groups (56-92%). Bile duct invasion to the first branch of the hepatic duct was more commonly observed in central ICC (43%) compared with the peripheral and intermediate ICC (0-8%). Lymph node metastasis was not observed in peripheral ICC, whereas it was frequently observed in intermediate and central ICC (39-44%). A Cox regression analysis revealed sufficient RDI (≥58.3%) of adjuvant chemotherapy (AC) significantly increased the length of DSS (HR: 0.205). Based on these data, we have proposed a location-specific therapeutic strategy as follows: peripheral ICC requires anatomical resection without lymphadenectomy; intermediate ICC requires anatomical resection with lymphadenectomy and sufficient doses of AC; and central ICC requires anatomical resection with extrahepatic bile duct resection, caudate lobectomy, lymphadenectomy, and sufficient doses of AC. Conclusion: We propose an intrahepatic tumor location-specific therapeutic strategy for ICC. This information could contribute to the appropriate therapeutic management of patients with ICC.