Relationship between the expression of PD-1/PD-L1 and 18F-FDG uptake in bladder cancer

Purpose Immunotherapy aimed at inhibiting the PD-1/PD-L1 immune checkpoint has been approved and used successfully for the treatment of bladder cancer. The identification of markers predictive of response to immune checkpoint inhibitors is critical to advancing the success of this therapy. 18 F-FDG PET/CT is a molecular imaging technique that can provide phenotypic information on malignant tumours. It is currently unknown whether there is a relationship between 18 F-FDG uptake and expression of PD-1/PD-L1 in bladder cancer. In this study, we investigated whether PD-1/PD-L1 expression is associated with 18 F-FDG uptake in bladder cancer, and whether 18 F-FDG PET/CT imaging can be used to predict the PD-1/PD-L1 status of bladder cancer. Methods A retrospective analysis was performed in 63 patients with bladder cancer who had undergone 18 F-FDG PET/CT before surgical resection. Maximum standardized uptake values (SUVmax) were determined. Results SUVmax was significantly higher in PD-1-positive patients than in PD-1-negative patients (33.0 ± 13.9 and 19.6 ± 14.2, respectively; P = 0.032), and in PD-L1-positive patients than in PD-L1-negative patients (29.1 ± 15.6 and 15.8 ± 11.4, respectively; P