Lymph node staging in gastric cancer: new criteria, old problems

PurposeOur study aims to test the prognostic accuracy of the N parameter of the 7th TNM in a Western series of D1-gastrectomies for gastric cancer (GC).MethodsRetrospectively considering a series of 224 non-metastatic GC patients who underwent surgery with curative intent and limited lymphadenectomy, we analyzed 5-year overall survival (OS) related to pN status according to both TNM editions (pN6 and pN7) and to lymph node ratio (LNR; LNR0, 0%, LNR1, 1–19%; LNR2, > 20%). We stratified pN6- and pN7-related OS by LNR.ResultsBoth pN6 and pN7 were shown to significantly stratify different subsets of GC patients, but there was no significant difference between pN71 and pN72, nor between pN62 and pN63. A multivariate model specific for pN7 eliminated the N2 group, while the pN6 model maintained all 3 N groups with highly discriminating hazard ratios. LNR was able to further stratify one category of pN6 (N2) and two categories of pN7 (N1 and N2).ConclusionsThe 7th TNM edition for GC does not seem to be superior to the 6th edition in evaluating the prognostic relevance of lymph-nodal status: in particular, it does not allow an accurate stratification of OS in patients with less than 6 positive lymph nodes.