Prognostic Significance of Lymph Node Metastases in Pancreatic Head Cancer Treated with Extended Lymphadenectomy: Not Just a Matter of Numbers

Abstract

The prognostic significance of variables related to nodal involvement (node status, number of disease-positive nodes [posNn], node ratio [Nr], and site of nodal metastases) in patients with resected pancreatic head cancer remains poorly defined. Clinical, operative, and pathologic data, including indexes of the burden and extent of nodal involvement, were analyzed in a consecutive series of 77 patients who underwent resection with extended lymphadenectomy for adenocarcinoma of the pancreatic head. Fifty-nine patients (77%) were found to have lymph node (LN) metastases. Median LN count, posNn, and Nr were 28 (10-54), 4 (1-29), and 14% (2%-55%), respectively. Twenty-six patients (44% of N1) had metastases limited to node level (NL) 1 (i.e., peripancreatic nodes); metastases up to NL2 (nodes along main arteries and hepatic hilum) and NL3 (preaortic nodes) were found in 21 (36%) and 12 (20%) patients, respectively. Interestingly, survival of patients with positive LN limited to NL1 was similar to that of node-negative patients (P = 0.407). posNn, Nr, and NL were all significant predictors of survival (P < 0.015). posNn and Nr proved to be an accurate proxy of NL involvement. The best cutoff of posNn was 2 and of and Nr was 10%. The level of nodal metastatic spread is a statistically significant prognostic factor in cancer of the pancreatic head. Both posNn and Nr are accurate proxy of NL and may improve patients' risk stratification.