As the perioperative
chemotherapy and conversion
therapy has been widely implemented on the standard treatment of
gastric cancer patients, it is of great importance to evaluate the efficacy of these patients accurately by effective methods. Being an important grading standard for histomorphological evaluation of excision specimens after
neoadjuvant chemotherapy, pathological
tumor regression grade (TRG) system is mainly used to assess the degree of
fibrosis of
tumor tissue and the proportion of
residual tumor cells. TRG evaluation may provide important information referring to clinical decision making and prognostic judgment, and may imply on different efficacy and survival rates. Currently, four TRG standards can be used to evaluate the efficacy of
neoadjuvant chemotherapy or translational
therapy for primary
gastric cancer, including Becker, Mandard, Ninomiya and Ryan, among which Ryan's 0-3 classification system is the most widely used. The main factors influencing the outcome of postoperative pathological TRG evaluation of
gastric cancer include
tumor localization, macroscopic observation and dissection of specimens, microscopic evaluation, as well as TRG evaluation criteria that are too complicated and difficult to operate. Although some studies have found that
tumor regression of
gastric cancer may be associated with some molecular markers, it may bring greater benefits to the choice of treatment decisions and prognosis judgment if further studies can confirm that specific
biomarkers can help estimate the efficacy of
neoadjuvant chemotherapy and translational
therapy for
gastric cancer after endoscopic biopsy.