[Gastric cancer: probability assessment after lymph node-negative staging and its consequences].
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.
Miralles-Tena
Juan Manuel
JM
Servicio de Cirugía General y del Aparato Digestivo, Hospital General de Castellón, Castellón, España. jmt@comcas.es
Escrig-Sos
Javier
J
Martínez-Ramos
David
D
Angel-Yepes
Vicente
V
Villegas-Cánovas
Carmen
C
Senent-Vizcaíno
Vicente
V
Salvador-Sanchís
José Luis
JL
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*