2021 Volume 36 Issue 2 Pages 120-127
Background: Although pembrolizumab was approved in Japan for the treatment of solid tumors with high-frequency microsatellite instability (MSI-H) which progressed after prior standard treatment in December 2018, there have been few reports of MSI-H pancreatic cancer in Japan because of its rarity. METHODS: We retrospectively examined 184 patients with unresectable pancreatic cancer (PC) who underwent MSI evaluation and the results of treatment using pembrolizumab for patients with MSI-H PC. Results: MSI-H was observed in 4 patients (2.2%), and pembrolizumab was administered to 3 patients. A partial response was achieved in 1 of 3 patients, which was a G-CSF-producing tumor. Conclusion: The frequency of MSI-H PC in our institution was 2.2%, consistent with previous reports. Since pembrolizumab treatment of patients with MSI-H PC could contribute to longer survival, MSI evaluation should be done proactively to increase the administration of promising treatment options.
