Evaluation of the impact of tumor deposits on prognosis in gastric cancer and a proposal for their incorporation into the AJCC staging system

Background: The aim of this study was to investigate the prognostic value of tumor deposits (TDs) in patients with gastric cancer after radical gastrectomy. Methods: We retrospectively reviewed 1518 patients who had undergone radical gastrectomy in Zhongshan Hospital between 2003 and 2011. Correlations between TDs and other clinicopathological characteristics were analyzed. Univariate and multivariate analysis of prognostic factors were conducted. The predictive ability of different staging systems incorporating TDs were evaluated. Results: The presence of TDs was found in 193 (13%) specimens. Large tumor size, proximal part, poor differentiated histology, advanced T stage, advanced N stage, lymphovascular invasion and perineural invasion were more common for patients with TDs. The Kaplan-Meier survival analysis revealed that survival of patients with TDs was significantly poorer than those without (P < 0.001). Multivariate analysis showed that presence of TDs was an independent prognostic factor for overall survival (hazard ratio (HR) = 1359, P = 0.001). We proposed a new staging system to incorporate TDs into TNM staging system that the presence of TDs would upstage N stage except for N3b patients. The results of chi-square, AUC, C index and AIC all showed that our revised scheme was better than the primary system and other schemes. Conclusions: The presence of TDs is an independent prognostic factor for gastric cancer patients. The TNM staging system would be more effective to predict the prognosis for gastric cancer patients after incorporating TDs using our revised scheme. (C) 2018 Elsevier Ltd, BASO- The Association for Cancer Surgery, and the European Society of Surgical Oncology. All rights reserved.