PD-L1-expressing Regulatory T Cells in Localized Prostate Cancer Patients Undergoing Iodine-125 Permanent Brachytherapy

Immunotherapy is currently revolutionizing the field in oncology. However, prostate cancer is poorly responsive to immune checkpoint inhibition. The combination of immunotherapy and radiotherapy is an emerging clinical treatment aradigm. X-ray radiation treatment can activate both the adaptive and innate immune systems through directly killing tumor cells, causing mutations in tumor-derived peptides, and causing localized inflammation that increases immune cell trafficking to tumors. Recently, preclinical study reported that immune checkpoint inhibition combined with radiotherapy treats CPRC with significant increases in median survival compared to drug alone.