Predicting Neoadjuvant Immunotherapy Responses in Gastroesophageal Cancer

Additional research and collaboration with other institutions may be necessary to further understand factors that influence how patients with mismatch repair deficient (dMMR) gastroesophageal cancer respond to neoadjuvant immunotherapy, according to Adrienne Bruce Shannon, MD.

Shannon, a complex general surgical oncology fellow from Moffitt Cancer Center, spoke with CancerNetwork^® about findings from a study she presented at the Society of Surgical Oncology (SSO) 2024 Annual Meeting assessing the extent to which patients with dMMR gastroesophageal cancers achieve pathologic responses to neoadjuvant immunotherapy.

According to Shannon, the study’s population is too small to definitively determine what might be predictive of responses in this disease. She suggested that larger populations are necessary for potentially clarifying predictive factors of response.

Findings from the study presented at SSO highlighted that gastroesophageal cancers appear to respond to neoadjuvant immune checkpoint inhibitor therapy, mirroring early clinical trial data.

Transcript:

When looking at all gastric cancers, there are limited studies, primarily in the translational medicine realm, that have looked at the tumor microenvironment. Essentially, when you have an increase in the CD8 cells demonstrating exhaustion of the immune response, that’s a poor prognostic factor, and those patients are less likely to respond to neoadjuvant immunotherapy. dMMR is [expressed in] 6% to 8% of gastric cancers, but truthfully, it’s quite rare. I don’t think that there’s much that we know at this stage that’s predictive—even within that small subsample—of who is going to respond. That’s something that is evolving and needs to be looked into.

It’s probably going to take collaborating with other institutions to try to get the numbers higher to really be able to understand what may is predictive and what’s not. But at this stage, our numbers are too small to be able to determine that but it’s something that probably needs to be looked into.

Reference

Shannon AB, Mehta RJ, Mok SR, et al. Pathologic response to neoadjuvant immunotherapy in DNA mismatch repair protein-deficient gastroesophageal cancers. Presented at the Society of Surgical Oncology 2024 Annual Meeting; March 20-24, 2024; Atlanta, GA. Abstract 94.