A systematic review of the prognostic value of lymph node ratio, number of positive nodes and total nodes examined in pancreatic ductal adenocarcinoma

BACKGROUND Pancreatic ductal adenocarcinoma is the most common pancreatic cancer. Five-year overall survival is currently 3.3-6.0%. The aim of this review was to evaluate the prognostic value of lymph node ratio, number of positive nodes and total nodes examined on overall survival rate following pancreatic resection. MATERIALS AND METHODS A literature search was conducted of MEDLINE, EMBASE, the Cochrane Library and Central Register of Controlled Trials and the Cochrane Database of Systematic Review databases, from January 1996 to January 2016. RESULTS Overall, 19 studies including 4,883 patients examined the relationship between lymph node ratio and overall survival. A high lymph node ratio was associated with decreased overall survival in 17 studies. A total of 12 studies examined the relationship between the number of positive nodes and overall survival, and 11 studies revealed that an increase in the number of positive nodes was associated with decreased overall survival. In 15 studies examining the relationship between the total nodes examined and overall survival, there was no association with overall survival in 12 studies. CONCLUSIONS Lymph node ratio and number of positive nodes are factors associated with overall survival in pancreatic ductal adenocarcinoma, but not total nodes examined.