Effect of the number of positive lymph nodes and lymph node ratio on prognosis of patients after resection of pancreatic adenocarcinoma

Abstract

The prognostic factors related to lymph node involvement [lymph node status, the number of positive lymph nodes, lymph node ratio (LNR)] and the number of nodes evaluated in patients with pancreatic adenocarcinoma after pancreatectomy are poorly defined. A total of 167 patients who had undergone resection of pancreatic adenocarcinoma from February 2010 to August 2011 were included in this study. Histological examination was performed to evaluate the tumor differentiation and lymph node involvement. Univariate and multivariate analyses were made to determine the relationship between the variables related to nodal involvement and the number of nodes and survival. The median number of total nodes examined was 10 (range 0-44) for the entire cohort. The median number of total nodes examined in node-negative (pN0) patients was similar to that in node-positive (pN1) patients. Patients with pN1 diseases had significantly worse survival than those with pN0 ones (P=0.000). Patients with three or more positive nodes had a poorer prognosis compared with those with the negative nodes (P=0.000). The prognosis of the patients with negative nodes was similar to that of those with one to two positive nodes (P=0.114). The median survival of patients with an LNR ≥0.4 was shorter than that of patients with an LNR <0.4 in the pN1 cohort (P=0.014). No significance was found between the number of total nodes examined and the prognosis, regardless of the cutoff of 10 or 12 and in the entire cohort or the pN0 and pN1 groups. Based on the multivariate analysis of the entire cohort and the pN1 group, the nodal status, the number of positive nodes and the LNR were all associated with survival. In addition to the nodal status, the number of positive nodes and the LNR can serve as comprehensive factors for the evaluation of nodal involvement. This approach may be more effective for predicting the survival of patients with pancreatic adenocarcinoma after pancreatectomy.