Benefit of lymph node dissection for perihilar and distal cholangiocarcinoma according to lymph node stations

Background The benefits of lymph node (LN) dissection at each station have not previously been fully investigated in perihilar cholangiocarcinoma (PHCC) and distal cholangiocarcinoma (DCC). Methods The efficacy index (EI) was calculated in patients who underwent surgery for PHCC (n = 134) and DCC (n = 135) by multiplying the frequency of metastasis to the LN station and the 5‐year overall survival (OS) rate of patients with metastasis to that station. Results In PHCC, the frequency of metastasis, 5‐year OS rates, and the EI in para‐aortic LNs (4.7%, 0%, and 0, respectively) and posterior pancreaticoduodenal LNs (8.1%, 0%, and 0, respectively) were lower than those in hepatoduodenal ligament LNs (30.1%, 24.1%, and 7.25, respectively) and LNs along the common hepatic artery (CHA) (16.2%, 15.0%, and 2.43, respectively). In DCC, these values were lower in LNs along the CHA (6.4%, 0%, and 0, respectively) than in the posterior pancreaticoduodenal LNs (31.2%, 34.5%, and 10.8, respectively), the hepatoduodenal ligament LNs (14.8%, 15.2%, and 2.25, respectively), and para‐aortic (4.0%, 25.0%, and 0.99, respectively) LNs. Conclusions According to the EI, this study raises concerns about the effectiveness of dissection in the posterior pancreaticoduodenal LNs in PHCC and LNs along the CHA in DCC. Terasaki and colleagues found that the efficacy index of pancreaticoduodenal lymph nodes in perihilar cholangiocarcinoma and lymph nodes along the common hepatic artery in distal cholangiocarcinoma was equal to or less than that of paraaortic lymph nodes, suggesting that these lymph nodes would be better treated as distant lymph nodes.