Gross Tumor Volume Of Gastric Adenocarcinoma Measured On Computed Tomography:Association With Stage

Objective:To explore the relationship between gross tumor volume(GTV)of gastric adenocarcinoma measured on computed tomography(CT)and tumor stage.Methods:The study enrolled continuously three hundred and fourteen gastric adenocarcinoma patients confirmed by biopsy(training cohort:n=215,validation cohort:n=99),all patients underwent contrast-enhanced thoracoabdominal CT within a week before or after diagnosis.The GTV was obtained on the portal venous phase CT image.In the training cohort,the Mann-Whitney U test,Kruskal-Wail H test and Spearman rank correlation test were performed to identify the association of GTV and tumor stage,and receiver operating characteristic curve(ROC)analysis was performed to assess the performance of GTV in distinguishing tumor stage.Kappa tests were used to verify the predictive effectiveness of ROC model of GTV distinguishing comprehensive stages in the validation cohort.Results:In the training cohort,Mann Whitney U test showed the gastric adenocarcinoma GTV in Ml stage was significantly higher than that in MO stage.Kruskal-Wail H test showed the higher the T stage,N stage and comprehensive stage of gastric adenocarcinoma,the greater the GTV(P<0.001 for all).The Spearman rank correlation test showed positive association of GTV with the M stage,T stage,N stage and comprehensive stage(r=0.429,0.632,0.493 and 0.665,respectively,P<0.001 for all).Receiver operating curve(ROC)analysis demonstrated that the GTV could differentiate M0 from the M1 stage with the area under the curve(AUC)of 0.784,distinguish T stages(T1 vs.T2-4,T1-2 vs.T3-4,and T1-3 vs.T4)with AUC of 0.913,0.885,0.794,respectively,distinguish N stages(N0 and N1-3,N0-1 and N2-3,N0-2 and N3)with AUC of 0.728,0.759,0.774,respectively,and distinguish comprehensive stages(Ⅰ vs.Ⅱ-Ⅳ,Ⅰ-Ⅱ vs.Ⅲ-Ⅳ and Ⅰ-Ⅲ vs.Ⅳ)with AUC of 0.908,0.857,0.784,respectively.In the validation cohort,the Kappa tests validated the ROC predictive models of the training cohort obtained good consistency with the comprehensive pathological stages for differentiating between Ⅰ from Ⅱ-Ⅳ stags,Ⅰ-Ⅱ from Ⅲ-Ⅳ stags andⅠ-Ⅲ from Ⅳ stags with K values of 0.718,0.798,and 0.754,respectively.Conclusion:Gross tumor volume of gastric adenocarcinoma measured on CT could distinguish T stages,N stages M stages and comprehensive stages with good performance.