Is Tumor Size A Predictor Of Preoperative N Staging In T2-T4a Stage Advanced Gastric Cancer?

Objective Lymph node metastasis is considered one of the most important prognosticfactors in gastric cancer. The N staging of gastric cancer is depended on the number ofmetastatic lymph nodes (LNs). At present, there is no reliable method for preoperativeN staging of gastric cancer. The aim of this study was to assess the relationshipbetween tumor size and preoperative N staging in patients with T2-T4a stageadvanced gastric cancer.Methods A total of697patients with gastric cancer in our hospital from January1999to February2008were analyzed. The correlations between the number of metastaticLNs and other clinicopathologic factors were investigated using univarite andmultivariate analysis. The relationship between tumor size and the metastatic LNs wasfurther evaluated by the generalized linear regression model. The Kappa consistencytest was used to test the agreement between predicted and pathologic N staging.Results Tumor size was normally distributed with a mean of6.10±2.79cm.Multivariate analysis showed that tumor size was independently (r=0.987, p<0.05)and linearly (R2=0.940, p<0.05) correlated with the number of metastatic LNs. Thenumbers of predicted metastatic LNs in patients with primary tumors <2.02cm,2.02-4.07cm,4.07-6.80cm, and≥6.80cm in size were0(Stage N0),1-2(Stage N1),3-6(Stage N2), and≥7(Stage N3), respectively. There was good agreement betweenN staging predicted by tumor size and pathologic N staging (Kappa value=0.531,p<0.05). The overall accuracy of tumor size for preoperative N staging was82.13%.The5-year survival rates of patients with predicted Stages N0, N1, N2, and N3were80.0%,71.1%,56.8%, and39.8%, respectively (p<0.05). There were no significantdifferences in the survival rates of patients with predicted N staging and thecorresponding pathologic N staging.Conclusions Tumor size is correlated with the number of LN metastases in patientswith stage T2-4a advanced gastric cancer. The measurements of tumor size can predict preoperative N staging.