title: Comparison of the 6th and 7th editions of the AJCC/UICC TNM staging system for gastric cancer focusing on the "N" parameter-related survival: the monoinstitutional NodUs Italian study.
abstract: BACKGROUND
  A large number of Asian population studies examined the difference between the 6th and the 7th tumor, node, metastasis (TNM) while it is still poorly validated among Caucasian populations. This is a retrospective study aimed at investigating the efficacy of the 7th edition American Joint Committee on Cancer (AJCC)/Union for International Cancer Control (UICC) staging system for gastric cancer focusing on the "N" parameter-related survival for prognostic assessment in gastric cancer patients of a single Western high-volume institution.
  
  
  METHODS
  From January 2002 to December 2009, the data of 274 patients with gastric cancer who underwent gastric surgery at the 8th General and Gastrointestinal Surgical Centre of the Second University of Naples were analyzed retrospectively. We collected data for patient demographics, tumor characteristics, surgical characteristics, and TNM stage. Particularly, the nodal status, with the number of dissected nodes and metastatic nodes, was reviewed from the pathology records. The same patient dataset was used to stage patients according to both the 6th and 7th edition criteria.
  
  
  RESULTS
  Age at surgery, tumor location, histological grade, Lauren's classification subtypes, and 6th and 7th AJCC/UICC N categories were found to have statistically significant associations with overall survival on univariate analysis. In the 6th edition staging system, the Kaplan-Meier plot did not show significant overlapped survival curves: significant differences were found between N0 and N1, P<.001; N1 and N2, P=.04; and N2 and N3, P<.001. On the contrary, in the 7th edition, among all five substages, there were similar survival curves between N categories 2 and 3a (P=.98) with a statistically significant discriminatory ability only between N1 versus N3b and N2 versus N3b (P=.02 and .04, respectively).
  
  
  CONCLUSIONS
  Based on analysis, we found that several clinicopathological variables, especially histological grade and Lauren's classification, were significant prognostic factors in our database. The 6th and 7th AJCC/UICC N classifications represent significantly independent prognostic factors, and the 6th AJCC/UICC N classification seems to be superior to the 7th AJCC/UICC N classification in terms of uniformity, differentiation, and monotonicity of gradients.
authors.affiliation: 8th General and Gastrointestinal Surgery, Department of Internal Medicine, Surgical, Neurological Metabolic Disease and Geriatric Medicine, Second University of Naples, Piazza Miraglia 2, 80138, Naples, Italy. marano.luigi@email.it.
authors.forename: Luigi
authors.initials: L
authors.lastname: Marano
authors.affiliation: 8th General and Gastrointestinal Surgery, Department of Internal Medicine, Surgical, Neurological Metabolic Disease and Geriatric Medicine, Second University of Naples, Piazza Miraglia 2, 80138, Naples, Italy. virginia.boccardi@email.it.
authors.forename: Virginia
authors.initials: V
authors.lastname: Boccardi
authors.affiliation: 8th General and Gastrointestinal Surgery, Department of Internal Medicine, Surgical, Neurological Metabolic Disease and Geriatric Medicine, Second University of Naples, Piazza Miraglia 2, 80138, Naples, Italy. braccio.bartolomeo@eamil.it.
authors.forename: Bartolomeo
authors.initials: B
authors.lastname: Braccio
authors.affiliation: 8th General and Gastrointestinal Surgery, Department of Internal Medicine, Surgical, Neurological Metabolic Disease and Geriatric Medicine, Second University of Naples, Piazza Miraglia 2, 80138, Naples, Italy. g-expo@libero.it.
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Esposito
authors.affiliation: 8th General and Gastrointestinal Surgery, Department of Internal Medicine, Surgical, Neurological Metabolic Disease and Geriatric Medicine, Second University of Naples, Piazza Miraglia 2, 80138, Naples, Italy. michelegrassia@live.it.
authors.forename: Michele
authors.initials: M
authors.lastname: Grassia
authors.affiliation: 8th General and Gastrointestinal Surgery, Department of Internal Medicine, Surgical, Neurological Metabolic Disease and Geriatric Medicine, Second University of Naples, Piazza Miraglia 2, 80138, Naples, Italy. mariannapetrillo@alice.it.
authors.forename: Marianna
authors.initials: M
authors.lastname: Petrillo
authors.affiliation: 8th General and Gastrointestinal Surgery, Department of Internal Medicine, Surgical, Neurological Metabolic Disease and Geriatric Medicine, Second University of Naples, Piazza Miraglia 2, 80138, Naples, Italy. opezze@hotmail.it.
authors.forename: Modestino
authors.initials: M
authors.lastname: Pezzella
authors.affiliation: 8th General and Gastrointestinal Surgery, Department of Internal Medicine, Surgical, Neurological Metabolic Disease and Geriatric Medicine, Second University of Naples, Piazza Miraglia 2, 80138, Naples, Italy. lelloporf@hotmail.it.
authors.forename: Raffaele
authors.initials: R
authors.lastname: Porfidia
authors.affiliation: 8th General and Gastrointestinal Surgery, Department of Internal Medicine, Surgical, Neurological Metabolic Disease and Geriatric Medicine, Second University of Naples, Piazza Miraglia 2, 80138, Naples, Italy. gianmarcoreda@libero.it.
authors.forename: Gianmarco
authors.initials: G
authors.lastname: Reda
authors.affiliation: 8th General and Gastrointestinal Surgery, Department of Internal Medicine, Surgical, Neurological Metabolic Disease and Geriatric Medicine, Second University of Naples, Piazza Miraglia 2, 80138, Naples, Italy. angelaromano@live.it.
authors.forename: Angela
authors.initials: A
authors.lastname: Romano
authors.affiliation: 8th General and Gastrointestinal Surgery, Department of Internal Medicine, Surgical, Neurological Metabolic Disease and Geriatric Medicine, Second University of Naples, Piazza Miraglia 2, 80138, Naples, Italy. mischettino@libero.it.
authors.forename: Michele
authors.initials: M
authors.lastname: Schettino
authors.affiliation: 8th General and Gastrointestinal Surgery, Department of Internal Medicine, Surgical, Neurological Metabolic Disease and Geriatric Medicine, Second University of Naples, Piazza Miraglia 2, 80138, Naples, Italy. angelo.cosenza@unina2.it.
authors.forename: Angelo
authors.initials: A
authors.lastname: Cosenza
authors.affiliation: 8th General and Gastrointestinal Surgery, Department of Internal Medicine, Surgical, Neurological Metabolic Disease and Geriatric Medicine, Second University of Naples, Piazza Miraglia 2, 80138, Naples, Italy. giuseppe.izzo@unina2.it.
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Izzo
authors.affiliation: 8th General and Gastrointestinal Surgery, Department of Internal Medicine, Surgical, Neurological Metabolic Disease and Geriatric Medicine, Second University of Naples, Piazza Miraglia 2, 80138, Naples, Italy. natale.dimartino@unina2.it.
authors.forename: Natale
authors.initials: N
authors.lastname: Di Martino
mesh_terms: D000230:Adenocarcinoma / Q000401:mortality* / Q000473:pathology* / Q000601:surgery; D000328:Adult; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D060787:Neoplasm Grading; D009367:Neoplasm Staging; D011379:Prognosis; D012189:Retrospective Studies; D013274:Stomach Neoplasms / Q000401:mortality* / Q000473:pathology* / Q000601:surgery; D015996:Survival Rate