Should Utilization of Lymphadenectomy Vary According to Morphologic Subtype of Intrahepatic Cholangiocarcinoma?

Objective. We sought to evaluate the utilization of lymphadenectomy (LND) and the incidence of lymph node metastasis (LNM) among different morphologic types of intrahepatic cholangiocarcinoma (ICC). Methods. Clinical data of patients undergoing curative-intent resection for ICC between 1990 and 2017 were collected and analyzed. The preoperative nodal status was evaluated by imaging studies, and the morphologic and lymph node (LN) status was collected on final pathology report. Results. Overall, 1032 patients had a mass-forming (MF) or intraductal growth (IG) ICC subtype, whereas 150 patients had a periductal infiltrating (PI) or MF+PI subtype. Among the 924 patients with MF/IG ICC subtype who had nodal assessment on preoperative imaging, 747 (80.8%) were node-negative, whereas 177 (19.2%) patients were suspicious for metastatic nodal disease. On final pathological analysis, 71 of 282 (25.2%) patients who had preoperative node-negative disease ultimately had LNM. In contrast, 79 of 135 (58.5%) patients with preoperative suspicious/metastatic LNs had pathologically confirmed LNM (odds ratio [OR] 4.2, p<0.001). Among the 129 patients with PI/MF+PI ICC subtype and preoperative nodal information, 72 (55.8%) were node-negative on preoperative imaging. In contrast, 57 (44.2%) patients had suspicious/metastatic LNs. On final pathologic examination, 45.3% (n=24) of patients believed to be node-negative on preoperative imaging had LNM; 68.0% (n=34) of patients who had suspicious/positive nodal disease on imaging ultimately had LNM (OR 2.6, p=0.009). Conclusion. Given the low accuracy of preoperative imaging evaluation of nodal status, routine LND should be performed at the time of resection for both MF/IG and PI/MF+PI ICC subtypes.