Yelena Y. Janjigian, MD, Reviews MSI as a Biomarker in for Localized Gastric Cancer

At the 2022 International Gastric Cancer Conference, Yelena Y. Janjigian, MD, chief of Gastrointestinal Oncology Service at Memorial Sloan Kettering Cancer Center, spoke with CancerNetwork® about microsatellite instability (MSI) as a biomarker for patients with localized gastric cancer and how it may be effective when deciding on treatment options.

Transcript:

For localized therapy, the most important biomarker that we could check—and it’s critical, even though that’s a rare biomarker—is microsatellite instability, or the MSI-high population. We know that these patients tend to do very well perhaps with surgery alone or even potentially with immunotherapy and then surgery. We also know, definitively, that immunotherapy is important in those patients with stage IV disease. Whether it will have a definitive foothold in the perioperative setting is still to be determined. What we also know is that those patients’ tumors tend to be chemotherapy resistant. You may harm your patient, as a surgeon, if you don’t know what their MSI status is, and then refer them to preoperative therapy. Data from the MAGIC study shows that peri-operative [epirubicin-based] therapy harms those patients. There are plenty of data to suggest that immunotherapy helps, but chemotherapy probably harms or is neutral. There’s a suggestion that chemotherapy in adjuvant setting may be neutral, but in the preoperative setting it’s harmful.

Reference

Cunningham D, Allum WH, Stenning SP, et al. Perioperative chemotherapy versus surgery alone for resectable gastroesophageal cancer. N Engl J Med. 2006;355(1):11-20. doi:10.1056/NEJMoa055531