Tumor volume as a prognostic factor was superior to the seventh edition of the pT classification in resectable gastric cancer

PurposeTo demonstrate that the seventh edition of the tumor-node-metastasis (TNM) classification for gastric cancer (GC) should be updated with the tumor volume (pTV) for the improvement of its prognostic prediction accuracy.MethodsA total of 497 stage TNM I-III GC patients who underwent curative gastrectomy between January 2003 and December 2007 in our center were enrolled in this study. pTV equals to (tumor diameter/2)2 × pT stage.ResultsIn the step 1 multivariate analysis, depth of invasion (pT) was confirmed to be an independent prognostic factors. However, when pTV was included in the step 2 multivariate analysis, pTV classification became significant, while pT classification disappeared. pT classification was substituted by pTV. For patients in each of the pT, significant differences in survival could always be observed among patients in different pTV classification. For patients in each pTV classification, prognosis was highly homologous between those in different pT classifications. TNM classification and the tumor volume-node-metastasis (TvNM) classification were directly compared for convenience. We found the TvNM classification (HR = 1.687, P < 0.001) was the most appropriately prognostic classification for predicting the OS of gastric cancer patients after curative surgery.ConclusionspTV maybe an independent prognostic factor in overall survival in GC, and pTV staging system maybe more reliable than the Union International Center Cancer and American Joint Committee (UICC/AJCC) on cancer pT system for prognostic assessment. pTV should be recommended as an important clinicopathologic variable for enhancement the accuracy of the prognostic prediction of GC patients in clinic.