The recommended therapeutic strategy for pathological stage II-III gastric cancer (GC) was gastrectomy followed by adjuvant chemotherapy. However, with the discovery of various molecular characterization of gastric cancer, oncologists found that the treatment of this type of patient should not be generalized. Thereinto, tumors that were deficient in DNA mismatch repair (dMMR) or high tumor mutation burden and hypermutator phenotype, termed microsatellite instability-high (MSI-H), were regarded as a particular type. Previous studies demonstrated that dMMR/MSI-H acts as a predictor of better outcome in resectable colon cancer but a poor response to adjuvant chemotherapy in stage II colon cancer patients.
1 Analogously, the individual patient data from 4 randomized trials (MAGIC, CLASSIC, ARTIST, and ITACA-S) showed that GC patients with dMMR/MSI-H did not benefit from adjuvant chemotherapy. Thus, the treatment strategy for dMMR/MSI-H GC patients remained controversial. …
