Prognostic impact of lymph node dissection in intrahepatic cholangiocarcinoma: a propensity score analysis

Purpose The clinical significance of lymph node dissection (LND) in patients with peripheral type intrahepatic cholangiocarcinoma (ICC) remains unclear. Although LND is usually performed for perihilar type ICC, there is no consensus on whether routine LND should be performed for peripheral type ICC. This study aimed to investigate the prognostic significance of LND in patients who underwent hepatectomy for peripheral type ICC. Methods This study included consecutive patients who underwent macroscopically curative initial hepatectomy for ICC at our hospital from 2000 to 2018. Among them, peripheral type ICCs with the macroscopic appearance of mass-forming (MF) or MF + periductal infiltrating (PI) types were analyzed. Propensity score analyses (1:1 matching and inverse probability treatment weighting) were adopted to adjust confounding variables. Overall survival (OS) and disease-free survival (DFS) were compared between the LND and no LND (NLND) groups. Results During the study period, 201 patients underwent hepatectomy for ICC. The number of peripheral ICC patients with MF type or MF + PI type was 142. The LND group comprised 94 patients and the NLND group comprised 48 patients. The N1 group showed significantly poorer OS and DFS than the N0 and NLND groups (P < 0.001). After propensity score adjustment, there were no significant differences in OS and DFS between the LND and NLND groups. Conclusions The prognostic impact of lymph node metastasis was significant; however, the therapeutic effect of LND was not demonstrated in peripheral type ICC. The indication of LND should be carefully considered on an individual patient basis.