[The defination of tumor deposit and its clinical significance in the diagnosis and treatment of gastric cancer].

Tumor deposit (TD) is a common histopathological finding in gastric cancer. With the improved ability of lymphadenectomy and pathological examination, the positive rate and harvested number of TD are also increasing. The role of TD in staging and prognosis prediction for gastric cancer patients is getting more attention. However, due to the lack of standardization and unification, the denomination, definition and diagnostic criteria are still controversial. The previous studies on the definition and diagnostic criteria of TD were reviewed to standardize the items and improve the awareness. TD is an independent prognostic factor in gastric cancer. Each TD should be counted separately as a lymph node in the final pN determination according to TNM staging system of the Union for International Cancer Control (UICC) or American Joint Committee on Cancer(AJCC) or Japanese classification of gastric carcinoma. But this rule is just an experience-based practice, without support from high-level evidence. Several studies have tried to incorporate TD into TNM staging system to improve the accuracy and discriminative ability. With the wide use of the 8th TNM staging system, how to incorporate TD into the new staging system in an easy and reasonable way still needs more investigations.