Histopathological regression of gastric adenocarcinoma after neoadjuvant therapy: a critical review.

As the perioperative chemotherapy has been widely implemented on the management of gastric cancer patients, heterogeneity of clinical outcomes has been evidenced in parallel to different histopathological regression pattern of gastric cancer cells. Tumor histological response to preoperative therapy has been graded by various systems in order to categorize the amount of regressive changes induced by chemotherapy in relation to residual tumor. In this context, tumor regression grading (TRG) systems might provide important prognostic information as the variety of tumor response may imply on different clinical outcomes with impact in survival rates.