The Research About The Lymphadenectomy For Pancreatic Ductal Carcinoma And The Prognosis Analysis

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 pancreatoduodenectomy of pancreatic carcinoma.Use two different methods of preliminary exploration to estimate the MNELN(Minimal Number of Examined Lymph Nodes) to ensure the pancreatic malignant tumors can be accurately detected by the examined lymph nodes.STUDY DESIGN Records of 151 consecutive patients with pancreatic ductal carcinoma in pancreatic head, who underwent R0 or R1 pancreatoduodenectomy 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. According to every lymph node detection for each growth number NELN, the change in the ratio of p N1 in patients with MNELN, to estimate the likelihood of the minimum number of examined lymph nodes. Binomial probability model is established to calculated the need to identify a positive lymph nodes required MNELN.RESULTS Overall survival rates were 70%, 49%, at 1, 2 years, respectively. The median numbers of evaluated lymph nodes and involved nodes were 7.4 and 0.9, respectively. Univariate analysis revealed that number of involved nodes, LNR, p T factor, and tumer stage correlated significantly(p < 0.05) with increased survival. By multivariate analysis, negative node metastasis and 0≤LNR<0.1, correlated independently with longer survival.0≤LNR<0.1,0≤LNR<0.2 correlated with longer survival in survival curves。With the number of examined lymph nodes NELN growth, changes in patients with p N1 ratio, p N1 ratio with NELN reached 11 the number has a significant proportion of p N1 ratio elevated and enter a platform period, no obvious increasing trend. The application of the two laws of probability to obtain the sample tested that we need least 24 lymph nodes to detect a positive lymph nodes.CONCLUSIONS LNR, but not number of metastatic nodes, is one of the most powerful prognostic factors after resection of pancreatic carcinoma. Research for MNELN need a larger sample to reach the convincing results.