@article {Chenjnumed.121.262250, author = {Ruohua Chen and Yining Wang and Yinjie Zhu and Yiping Shi and Lian Xu and Gang Huang and Jianjun Liu}, title = {The added value of 18F-FDG PET/CT compared to 68Ga-PSMA PET/CT in patients with castration-resistant prostate cancer}, elocation-id = {jnumed.121.262250}, year = {2021}, doi = {10.2967/jnumed.121.262250}, publisher = {Society of Nuclear Medicine}, abstract = {Purpose: The 68Ga-PSMA PET/CT is a commonly used imaging modality in prostate cancers. However, few studies have compared the diagnostic efficiency between 68Ga-PSMA and 18F-FDG PET/CT and evaluated whether a heterogeneous metabolic phenotype (especially PSMA-FDG+ lesions) exists in patients with castration-resistant prostate cancer (CRPC). We determined the added value of 18F-FDG PET/CT compared to 68Ga-PSMA PET/CT in CRPC patients and identified CRPC patients who may benefit from additional 18F-FDG PET/CT. Methods: Data of 56 patients with CRPC who underwent both 68Ga-PSMA and 18F-FDG PET/CT from May 2018 to February 2021 were retrospectively analysed. Patients were classified into two groups with or without PSMA-FDG+ lesions. The differences in patient characteristics between the two groups and predictors of patients who having at least one PSMA-FDG+ lesion were analysed. Results: Although both the detection rate (75.0\% vs. 51.8\%, P = 0.004) and positive lesion number (135 vs. 95) of 68Ga-PSMA PET/CT were higher than 18F-FDG PET/CT, there were still 13/56 (23.2\%) patients with at least one PSMA-FDG+ lesion. The prostate-specific antigen (PSA) and Gleason score were both higher in the patients with PSMA-FDG+ lesions than in those without PSMA-FDG+ lesions (P = 0.04 and P\<0.001, respectively). Multivariate regression analysis showed that the Gleason score (>=8) and PSA (>=7.9 ng/mL) were associated with the detection rate of patients who had PSMA-FDG+ lesions (P = 0.01 and P = 0.04, respectively). The incidences of having PSMA-FDG+ lesions in low-probability (Gleason score\<8 and PSA\<7.9 ng/mL), medium-probability (Gleason score>=8 and PSA\<7.9 ng/mL or Gleason score\<8 and PSA>=7.9 ng/mL), and high-probability (Gleason score>=8 and PSA>=7.9 ng/mL) groups were 0\%, 21.7\%, and 61.5\%, respectively (P\<0.001). Conclusion: Gleason score and PSA are significant predictors for PSMA-FDG+ lesions, and CRPC patients with high Gleason score and PSA may benefit from additional 18F-FDG PET/CT.}, issn = {0161-5505}, URL = {https://jnm.snmjournals.org/content/early/2021/04/23/jnumed.121.262250}, eprint = {https://jnm.snmjournals.org/content/early/2021/04/23/jnumed.121.262250.full.pdf}, journal = {Journal of Nuclear Medicine} }