A recent study by dr. Nicole van Grieken et al. at UMC Amsterdam has evaluated the efficacy of chemotherapy in gastric cancer patients with microsatellite instability (MSI).
The standard of care for non-metastatic gastric cancers includes surgery and perioperative chemotherapy. However, it is observed that patients with genomic alterations (MSI) can die when treated with chemotherapy. They are also more likely to experience additional side effects. Based on these observations, clinicians at UMC Amsterdam investigated whether gastric cancer patients with MSI have poor survival outcomes after treatment with chemotherapy as expected, and compared the survival outcomes in GC patients without MSI.
The study found that MSI gastric cancer is a favourable prognostic character for women. Moreover, treatment with chemotherapy (5-FU) was showed positive benefits in rare cases. However, the study could not conclude that MSI gastric cancer benefits do not benefit from chemotherapy. Therefore, it remains to be determined if MSI can be used as a response marker to chemotherapy.
Intriguingly, the researchers found that patients with MSI gastric tumours who did respond to chemotherapy showed strong mucus formation. These new clinical features could be used for stratifying MSI patients who may respond well to chemotherapy. However, these observations need to be validated in studies with more patients.
Taken together, in case the MSI gastric cancer patients do not tolerate the chemotherapy well, stopping the therapy should be considered.