Purpose: To evaluate the value of CT tumor volumetry for predicting T, N stage for gastric cancer after chemotherapy with pathologic results as the reference standard.
Methods: This study retrospectively evaluated 42 patients diagnosed with gastric cancer undergoing chemotherapy followed by surgery. Pre-, post-treatment CT tumor volumes(T-vol) were measured in portal venous phase and volume reduction ratio were calculated. The correlations between pre-, post-treatment T-vol, reduction ratio and pathologic stages were analyzed. Receiver operator characteristics (ROC) analyses were also performed to assess diagnostic performance for prediction of downstage to T0-2 stage and N0 stage.
Results: Pre-, post-treatment T-vol, and T-vol reduction ratio were significantly correlated with T stage (rho: 0.329, 0.546, -0.422, respectively). Post-treatment T-vol and T-vol reduction ratio were significantly correlated with N stage (rho:0.442, -0.376, respectively). The differences between T0-2 and T3-4 stages in pre-, post-treatment T-vol and T-vol reduction ratio were statistically significant (P=0.05, P<0.001, P=0.002 respectively). The differences between N0 and ≥N1 groups were also statistically significant (P=0.005 for post-treatment T-vol, P=0.016 for reduction ratio, respectively). The area under the ROC curves (AUCs) for identification of T0-2 groups were 0.70 for pre-treatment T-vol, 0.88 for the post-treatment T-vol, 0.82 for T-vol reduction ratio, respectively. And AUCs were 0.78 for post-treatment T-vol, 0.74 for T-vol reduction ratio for identification of N0 groups.
Conclusion: CT tumor volumetry with gastric cancer especially post-treatment T-vol had potentially value for predicting histopathologic T and N stage after chemotherapy.