The prognostic value of tumor deposits and the impact on the TNM classification system in esophageal cancer patients.

OBJECTIVE To explore the prognostic significance of tumor deposits (TDs), isolated tumor foci lacking residual lymph nodes, in esophageal cancer (EC). METHODS A retrospective review of patients with EC undergoing esophagectomy between 2005 and 2017 was conducted. The prognostic value of TD was evaluated using a Cox regression model. Patients from different sources and periods were split into discovery and validation sets. A propensity score matching model was used in the validation set to reduce the confounding bias. The impact of TD on the TNM classification system was evaluated. RESULTS The discovery and validation sets included 179 and 2875 patients, respectively. Propensity-matched patients with and without TDs were constructed in the validation set with 132 patients in each group. Overall survival (p < .001 and p = .004, respectively) and disease-free survival (p < .001 and p = .019, respectively) were both decreased in TD positive patients in the discovery set and propensity-matched groups of validation set. Classifying patients with TDs into pN3 stage improved the discriminative power of the current TNM staging system. CONCLUSIONS TD is an independent prognostic factor for EC. The inclusion of TD in the TNM staging system may upstage appropriate patients to help guide therapy, and future studies are warranted.