Consideration of tumor size improves the accuracy of TNM predictions in patients with gastric cancer after curative gastrectomy

To investigate whether addition of tumor size improves the prognostic accuracy of the UICC 7th TNM staging system in gastric cancer patients who underwent radical surgery (R0 resection).The clinical and pathological data and postoperative 5-year survival rate of 507 patients with gastric cancer who underwent radical surgery (R0 resection) in our department from January 2004 to June 2006 were evaluated retrospectively. The prognostic accuracy of conventional UICC 7th TNM staging was compared with that of UICC 7th TNM staging plus tumor size. The ability of tumor size to improve the 95% confidence interval (CI) of postoperative 5-year survival rate in gastric cancer patients was assessed.Of the 507 patients, 470 (92.7%) were followed up. The five-year survival rate of these patients was 50.4%. The survival rates of patients with pT1, pT2, pT3, and pT4 stage tumors were 89.3%, 72.4%, 36.9%, and 23.7%, respectively (P < 0.05), and the survival rates of patients with pN0, pN1, pN2, and pN3 stage tumors were 75.2%, 68.8%, 46.7%, and 21.3% (P < 0.05). Depth of invasion, lymph node metastasis stage, metastatic lymph node ratio (MLR), lymphatic invasion and tumor size were independent predictors of patient prognosis. The accuracy of UICC 7th TNM staging in predicting 5-year survival was 75.4% and the accuracy of tumor size plus the UICC 7th TNM staging was 77.9% (P < 0.05). This combination improved the 95% CI of postoperative 5-year survival rate in gastric cancer patients.Tumor size can improve the accuracy of UICC 7th TNM staging in predicting survival in gastric cancer patients following radical surgery (R0 resection). Tumor size is likely to be another important indicator in future UICC-TNM staging systems for gastric cancer patients.