Rational Extent of Regional Lymphadenectomy and the Prognostic Impact of the Number of Positive Lymph Nodes for Perihilar Cholangiocarcinoma.

ABSTRACT

BACKGROUND: The definition and classification of regional nodes are not standardized for perihilar cholangiocarcinoma. This study aimed to clarify the rational extent of regional lymphadenectomy and to elucidate the impact of number-based regional nodal classification on survival of patients with this disease. METHODS: Data of 136 patients with perihilar cholangiocarcinoma who underwent surgery were reviewed. The incidence of metastasis and the survival of patients with metastasis were calculated for each node group. RESULTS: The incidence of metastasis for the node groups in the hepatoduodenal ligament (denoted as no. 12) ranged from 3.7% to 25.4%, with 5-year disease-specific survival of 12.9% to 33.3% for patients with metastasis. The incidences of metastasis in the common hepatic artery (no. 8) and posterior superior pancreaticoduodenal (no. 13a) node groups were 14.4% and 11.2%, respectively, with 5-year disease-specific survival rates of 16.7% and 20.0% for the patients with metastasis. When these node groups were defined as regional nodes, the 5-year disease-specific survival rates for the patients with pN0 (n = 80), pN1 (1-3 positive nodes, n = 38), and pN2 (≥ 4 positive nodes, n = 18) were 61.4%, 22.9%, and 17.6%, respectively (p < 0.001). The pN classification was independently associated with disease-specific survival (p < 0.001). When only the no. 12 node groups were regarded as regional nodes, pN classification failed to stratify the patients prognostically. CONCLUSIONS: No. 8 and no. 13a node groups should be considered regional nodes in addition to no. 12 node groups and should be dissected. The number-based regional nodal classification allows patients with this disease to be stratified prognostically.