How to Interpret the Pathological Report before and after Endoscopic Submucosal Dissection of Early Gastric Cancer

Possible lymph node metastasis (LNM) and residual cancer are major concerns in endoscopic submucosal dissection (ESD) for early gastric cancer. To reduce the risk of LNM and cancer recurrence, the proper indications for ESD should be considered. Histology, size, depth of invasion, and presence of ulceration should be thoroughly evaluated before proceeding with ESD. However, with incomplete information, discrepancies often arise between the pathological diagnosis based on the forceps biopsy and that based on the totally resected specimen. In addition, the presence of lymphovascular involvement and histological homogeneity can be clarified only after ESD. If the pathological diagnosis changes after ESD, we should reevaluate the curativeness and reformulate the goal of treatment. Additional surgery is a reasonable strategy for non-curative ESD, but a patient's other health conditions should also be considered. It is simple to read pathological reports before and after ESD, but it can be a complicated art to interpret the report and formulate an optimal approach. In this review, various considerations regarding the pathological diagnosis will be discussed.