Neoadjuvant Treatment Options for MSI-High Gastroesophageal Junction Cancers

Anup Kasi, MD, University of Kansas Cancer Center, Kansas City, KS, discusses the debate on treatment options for patients with microsatellite instability-high locally resectably gastric or gastroesophageal junction adenocarcinoma. This debate was held at the 2023 Great Debates and Updates in GI Malignancies in Chicago.

Dr Kasi defended the position of chemotherapy for this patient population and explains the evidence that could support this treatment choice, as well as the how he would approach these patients in his real practice.

Transcript:

Hi, I'm Anup Kasi. I'm a GI medical oncologist and an associate professor at the University of Kansas Cancer Center. I'm here at the 2023 Great Debates & Updates in GI malignancies in Chicago, and the debate I participated in was examining the question of a neoadjuvant combined immunotherapy versus chemotherapy for MSI-high resectable gastric and gastroesophageal junction cancers.

It was a hard debate to defend because my topic was to defend chemotherapy, neoadjuvant chemotherapy, and whenever we hear the “MSI,” that buzzword, immunotherapy automatically comes to our minds. However, what we have to keep in mind, is the level of evidence that we have as of now is still in favor of chemotherapy. FLOT as the standard of care for all-comer, resectable gastric, or gastroesophageal junction cancer tumors.

However, when we look at the MSI-high tumors, there have been meta-analyses that have looked at doublet chemotherapies and have shown actually detrimental outcomes if MSI-high tumors are treated with doublet chemotherapies.

But, with FLOT, which is a triplet chemotherapy, and which includes a taxine-based treatment, studies with real world evidence have shown that MSI-high patients still derive benefit. It was interesting that one of the studies called the PROSECCO study and the other one is called the RealFLOT study, showed the node-negative rate at the time of surgery was much higher for the MSI-high cohort, 68% versus 30% for the [microsatellite stable] MSS cohort of patients. Of course, these are retrospective studies, so we have to take that with a grain of salt.

That's the position I had to defend. However, in real practice though, I do feel that these patients that are MSI-high, if I see them in the clinic, I would definitely treat them with immunotherapy because the response rates are much, much higher and potential for cure and some patients we can even avoid surgery.

Source:

Kasi A. “Debate: Neoadjuvant Combined Immunotherapy vs Chemotherapy for MSI-H Locally Resectable Gastric or Gastroesophageal Junction Adenocarcinoma (GAC/GEJAC) – Chemotherapy.” Presented at: Great Debates and Updates in Gastrointestinal Malignancies; March 30-April 1, 2023; Chicago, IL