Clinical Significance of Tumor Deposits in Gastric Cancer: a Retrospective and Propensity Score-Matched Study at Two Institutions.

<bold>Background: </bold>Gastric cancer (GC) treatment is largely determined by tumor stage. Despite improvements in the mode of treatment of various types of advanced disease, staging is still evolving. The role of tumor deposits (TDs) in staging remains debated. The purpose of this research is to investigate the relationship between TDs and prognosis in GC.<bold>Methods: </bold>A total of 3098 patients were considered eligible for prognostic analysis (2706 patients in the TDs-negative group and 392 patients in the TDs-positive group). A one-to-one propensity score-matching analysis was performed using a logistic regression mode and the following covariates: age, gender, tumor location, size, differentiation, perineural invasion, lymphovascular invasion, pTNM stage, type of gastrectomy, and the number of lymph nodes retrieved between TDs-negative and TDs-positive group, then 323 patients in each group were analyzed. Univariate and multivariate analyses of prognostic factors were conducted accordingly. The predictive ability of different staging system incorporating TDs was evaluated.<bold>Results: </bold>TDs were present in 14.5% cases and almost all of the patients (99%) suffered from advanced GC. Multivariate analysis showed that pN stage, chemotherapy, and TDs were the independent prognostic factors. The TDs-positive group showed a lower rate of 5-year disease-free survival compared with the TDs-negative group in all patients, stage II, and stage III patients (p = 0.001, 0.029, and 0.003, respectively). The 5-year disease-free survival for patients with TDs and without TDs was 27.6% and 34.4%, respectively.<bold>Conclusions: </bold>Our research shows that TDs are closely associated with prognosis in GC. TDs should be incorporated into the TNM staging system, which could then accurately improve the staging reliability and prognostic assessment. [ABSTRACT FROM AUTHOR]