Association between PD-L1 expression and ¹⁸F-FDG uptake in ovarian cancer

Objective: Immunotherapy for programmed cell death 1 (PD-1) and its ligand, PD-L1, has been considered an effective treatment for ovarian cancer. ¹⁸F-labeled fluoro-2-deoxyglucose positron emission tomography/computed tomography (¹⁸F-FDG PET/CT) is a widely used noninvasive imaging tool for diagnosing several cancers. In this study, we investigated the association between PD-L1 expression and the maximum standardized uptake value (SUVmax) using ¹⁸F-FDG PET/CT. Methods: We retrospectively analyzed clinical data of patients with ovarian cancer who underwent ¹⁸F-FDG PET/CT. Patients were categorized into two groups according to PD-L1 expression results. The relationship between clinicopathological characteristics of patients with ovarian cancer and PD-L1 expression was examined. Results: SUVmax was significantly higher in PD-L1-positive tumors than in PD-L1-negative tumors (16.1 ± 5.2 and 12.7 ± 7.0, respectively; p = 0.026). There were no significant differences in age, histologic type, and tumor grade between the PD-L1-negative and PD-L1-positive groups. The receiver operating characteristic curve analysis demonstrated that the highest accuracy (61.8%) for predicting PD-L1 expression was obtained with an SUVmax cutoff value of 10.5. Conclusion: There was a significant correlation between ¹⁸F-FDG uptake and PD-L1 expression, suggesting a role of ¹⁸F-FDG PET/CT in selecting ovarian cancer candidates for anti-PD-L1 antibody therapy.