ORIGINAL ARTICLE – GASTROINTESTINAL ONCOLOGY Tumor Size as a Recommendable Variable for Accuracy of the Prognostic Prediction of Gastric Cancer: A Retrospective Analysis of 1,521 Patients Jingyu Deng, MD, Rupeng Zhang, MD, Yuan Pan, MD, Xuewei Ding, MD, Mingzhi Cai, MD, Yong Liu, MD, Honggen Liu, MD, Tao Bao, MD, Xuguang Jiao, MD, Xishan Hao, MD, and Han Liang, MD Department of Gastric Cancer Surgery, National Clinical Research Center for Cancer, City Key Laboratory of Tianjin Cancer Center, Tianjin Medical University Cancer Hospital, Tianjin, China ABSTRACT Background. It is still controversial whether tumor size (Ts) should be considered an important indicator for evaluation the prognosis of gastric cancer (GC). The pur- pose of this study was to elucidate the prognostic prediction superiority of Ts in the large-scale cohort of GC patients. Methods. Data from 1,521 patients who underwent the curative resection were analyzed for demonstration the prognostic value of Ts. In addition, a tumor size-node- metastasis (TsNM) classification system was proposed to evaluate the comparative superiorities of the prognostic prediction of GC patients. Results. With the univariate and multivariate analyses, Ts was identified as an independently prognostic predictor of GC patients, as was T stage. Ts was demonstrated to have smaller Akaike information criterion and Bayesian Infor- mation Criterion values within the Cox regression analyses than shown by T stage, which represented the optimum prognostic stratification. TsNM classification was also found to be competent for accurately prognostic evaluation of GC patients. The matched case–control logistic regres- sion showed that TsNM classification could provide very powerful discriminations of patients’ overall survival, compared with TNM classification. Additionally, Ts stage was found to enhance the survival discriminations in patients with certain clinicopathological characteristics, including male gender, T4a stage, N0 stage, diffuse type of Lauren classification, or age B60 years. Conclusions. Ts should be recommended as an important clinicopathologic variable to enhance the accuracy of the prognostic prediction of GC clinical patients. T stage of the TNM classification for gastric cancer (GC) is considered a simple and credible category of the depth of tumor invasion. However, it is still controversial whether or not the current T stage is the most appropriate category representing the overall biological characteristics of the primary tumor for accurate prognostic prediction of GC patients. 1,2 Actually, both transformation and growth of cancer cells are the natural history of malignancies. Growth of malignant tumor is primarily characterized by the state of its pathological or morphological variables such as size of tumor, invasion of submucosa, and metastasis to lymph nodes or distant organs, which determine whether the tumor manifests any detectable clinical symptoms. 3 Tumor size (Ts), given as the maximum diameter of tumor, could provide important information useful for evaluating the potential impact of tumor doubling time on screening programs in terms of the degree of improvement in prog- nosis. 3,4 So far, Ts is considered an independent indictor for accurately evaluating the prognosis of many kinds of malignant tumors. 5–13 Recently, several authors proposed consideration of the prognostic evaluation value of Ts in given subgroups of GC patients. 14–22 In view of the different subgroups of GC patients and the inconsistent cutoff values of Ts in aforementioned studies, it is very hard to precisely estimate the clinical applicability and superiority of Ts in a large-scale cohort of patients. In this study, we intended to test the clinical superiority of Ts for prognostic prediction in a large group Ó Society of Surgical Oncology 2014 First Received: 16 April 2014; Published Online: 26 August 2014 H. Liang, MD e-mail: tjlianghan@sohu.com Ann Surg Oncol (2015) 22:565–572 DOI 10.1245/s10434-014-4014-x