Number of Metastatic Lymph Nodes, but Not Lymph Node Ratio, Is an Independent Prognostic Factor after Resection of Pancreatic Carcinoma

BACKGROUND: This study evaluated the prognostic significance of the number of metastatic lymph nodes and the ratio of metastatic nodes to total number of examined lymph nodes (lymph node ratio, LNR) after resection of pancreatic carcinoma. STUDY DESIGN: Records of 119 consecutive patients with pancreatic ductal carcinoma, who underwent R0 or RI pancreatectomy with regional node dissection, were reviewed retrospectively. Clinical factors, pathologic factors including number of metastatic nodes and LNR, and survival were analyzed by univariate and multivariate analyses. RESULTS: Overall survival rates were 78%, 28%, and 20% at 1, 3, and 5 years, respectively. The median numbers of evaluated lymph nodes and involved nodes were 28 and 3, respectively. Univariate analysis revealed that tumor location, postoperative adjuvant chemotherapy, tumor differentiation, choledochal invasion, portal or splenic vein invasion, extrapancreatic nerve plexus invasion, resection margin status, node status, number of involved nodes, LNR, International Union against Cancer (UICC) pT factor, and UICC stage correlated significantly (p < 0.05) with increased survival. By multivariate analysis, negative node metastasis (p = 0.008) and 0 or 1 involved node (p = 0.004), but not LNR, correlated independently with longer survival. The 1-, 3-, and 5-year survival rates of patients with 0 or 1 metastatic node and patients with 2 or more metastatic nodes were 91%, 48%, and 40% and 66%, 10%, and 0%, respectively. CONCLUSIONS: The number of metastatic nodes, but not LNR, is one of the most powerful prognostic factors after resection of pancreatic carcinoma. (J Am Coll Surg 2010;211:196-204. (C) 2010 by the American College of Surgeons)