Year: 2025
Type: article
Study design: Case Report
Abstract: Introduction: The use of pembrolizumab in patients with microsatellite instability-high (MSI-high) and tumor mutation burden-high (TMB-high) prostate cancer in Japan is not widely reported. Here, we report the case of a patient with MSI-high and TMB-high prostate cancer who responded well to pembrolizumab after multiple systemic treatments. Case Presentation: A 68-year-old Japanese man was diagnosed with cT4N1M1a prostate cancer. He was treated with several androgen receptor signaling inhibitors and chemotherapy. After intense systemic treatment, disease progression was confirmed, and genomic testing detected MSI-high and TMB-high. However, treatment with pembrolizumab resulted in marked prostate-specific antigen reduction and significant shrinkage of metastases. Conclusion: Genomic tests should be considered for high-grade tumors. MSI-high and TMB-high prostate cancer responded well to pembrolizumab in this case, but patients should be carefully monitored for the development of side effects after administration of pembrolizumab.
Source: IJU Case Reports
DOI: 10.1002/iju5.70062
Authors: Satoshi Muraoka, Hisanobu Tosuji, Yuya Iwahashi, Hiroki Kawabata, Ryusuke Deguchi, Takahito Wakamiya, Shimpei Yamashita, Yasuo Kohjimoto, Isao Hara
Institution: Wakayama Medical University
Language: English
Subfield: Pulmonary and Respiratory Medicine
Field: Medicine
Domain: Health Sciences
Open Access status: gold
Estimated APC paid: $4,960
Funder: Wakayama Medical University
OpenAlex ID: W4411503862