Comparison Of Three Lymph Node Staging Systems For Pancreatic Neuroendocrine Tumors

Background:The American Joint Committee on Cancer(AJCC)staging for pancreatic neuroendocrine tumors(PNETs)based on the number of positive lymph nodes(p Ns)is the most widely accepted nodal staging system.New nodal staging schemes that take both the number of p Ns and the number of examined lymph nodes(ELNs)into consideration have emerged as useful prognostic tools.The aim of the current study was to determine the most effective nodal staging system,among the 8th edition AJCC N staging(or p N staging),lymph node ratio(LNR),and log odds of positive lymph nodes(LODDS),for predicting the cause-specific survival(CSS)of patients with PNETs.Methods:The clinicopathological and prognostic data of 2,295 patients from the Surveillance,Epidemiology,and End Results(SEER)database,diagnosed with PNETs between 1988–2015,were reviewed retrospectively.Results:A multivariate analysis identified p N and LNR staging as independent prognostic factors,but not LODDS.The p N staging exhibited higher C‐index and area under the curve values than those of the LNR and LODDS,indicating better predictive discriminatory capacity.No significant difference in the survival of patients was observed within the same p N staging subgroup according to the number(high or low)of ELNs.In contrast,intra-group heterogeneity was seen with use of LNR and LODDS staging,due to overestimation of the risk of insufficient ELNs.And LODDS failed to stratify patients without lymph nodes metastasis into different risk groups.Conclusions:The 8th edition AJCC N staging for PNETs is more reliable than LNR or LODDS staging for predicting the CSS of PNETs.