title: [Gastric cancer: probability assessment after lymph node-negative staging and its consequences].
abstract: OBJECTIVE
  To provide an approach to calculating the probability of error after lymph node-negative staging in gastric cancer.
  
  
  METHODS
  Retrospective data of 75 gastric resections for cancer were used to calculate the probability of error in general, according to T staging of the TNM classification (6th edition) and according to the type of lymphadenectomy performed. A modification of a procedure based on Bayes' theorem was used.
  
  
  RESULTS
  For all tumors, at least 11 negative lymph nodes were required to ensure a true pN0. Two lymph nodes were required for T1 tumors, 11 for T2 tumors, and 14 for T3 tumors. A greater number of lymph nodes were required for a D2 lymphadenectomy than for a D1 lymphadenectomy. However, in D2 lymphadenectomy, pN0 stages were almost always reliable, while in D1 lymphadenectomy 24% of stagings were unreliable.
  
  
  CONCLUSIONS
  The present study describes a simple and reproducible mathematical model that could help surgeons to determine the accuracy of lymph node-negative stages in a substantial group of patients with gastric cancer.
authors.affiliation: Servicio de Cirugía General y del Aparato Digestivo, Hospital General de Castellón, Castellón, España. jmt@comcas.es
authors.forename: Juan Manuel
authors.initials: JM
authors.lastname: Miralles-Tena
authors.forename: Javier
authors.initials: J
authors.lastname: Escrig-Sos
authors.forename: David
authors.initials: D
authors.lastname: Martínez-Ramos
authors.forename: Vicente
authors.initials: V
authors.lastname: Angel-Yepes
authors.forename: Carmen
authors.initials: C
authors.lastname: Villegas-Cánovas
authors.forename: Vicente
authors.initials: V
authors.lastname: Senent-Vizcaíno
authors.forename: José Luis
authors.initials: JL
authors.lastname: Salvador-Sanchís
mesh_terms: D001499:Bayes Theorem; D003951:Diagnostic Errors; D005260:Female; D006801:Humans; D008198:Lymph Nodes / Q000473:pathology; D008297:Male; D008875:Middle Aged; D015233:Models, Statistical; D009367:Neoplasm Staging; D012189:Retrospective Studies; D013274:Stomach Neoplasms / Q000473:pathology*