TY - JOUR T1 - The Added Value of <sup>18</sup>F-FDG PET/CT Compared with <sup>68</sup>Ga-PSMA PET/CT in Patients with Castration-Resistant Prostate Cancer JF - Journal of Nuclear Medicine JO - J Nucl Med SP - 69 LP - 75 DO - 10.2967/jnumed.120.262250 VL - 63 IS - 1 AU - Ruohua Chen AU - Yining Wang AU - Yinjie Zhu AU - Yiping Shi AU - Lian Xu AU - Gang Huang AU - Jianjun Liu Y1 - 2022/01/01 UR - http://jnm.snmjournals.org/content/63/1/69.abstract N2 - 68Ga-prostate-specific membrane antigen (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 68Ga-PSMA–negative [−], 18F-FDG–positive [+] lesions) exists in patients with castration-resistant prostate cancer (CRPC). We determined the added value of 18F-FDG PET/CT compared with 68Ga-PSMA PET/CT in CRPC patients and identified CRPC patients who may benefit from additional 18F-FDG PET/CT. Methods: The data of 56 patients with CRPC who underwent both 68Ga-PSMA and 18F-FDG PET/CT from May 2018 to February 2021 were retrospectively analyzed. The patients were classified into 2 groups: with or without 68Ga-PSMA−, 18F-FDG+ lesions. The differences in patient characteristics between the 2 groups and predictors of patients who have at least 1 68Ga-PSMA−, 18F-FDG+ lesion were analyzed. Results: Although both the detection rate (75.0% vs. 51.8%, P = 0.004) and the number of positive lesions (135 vs. 95) were higher for 68Ga-PSMA PET/CT than for 18F-FDG PET/CT, there were still 13 of 56 (23.2%) patients with at least 1 68Ga-PSMA−, 18F-FDG+ lesion. Prostate-specific antigen (PSA) and the Gleason score were both higher in patients with 68Ga-PSMA−, 18F-FDG+ lesions than in those without (P = 0.04 and P &lt; 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 68Ga-PSMA−, 18F-FDG+ lesions (P = 0.01 and P = 0.04, respectively). The incidences of having 68Ga-PSMA−, 18F-FDG+ lesions in low-probability (Gleason score &lt; 8 and PSA &lt; 7.9 ng/mL), medium-probability (Gleason score ≥ 8 and PSA &lt; 7.9 ng/mL or Gleason score &lt; 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 &lt; 0.001). Conclusion: Gleason score and PSA are significant predictors of 68Ga-PSMA−, 18F-FDG+ lesions, and CRPC patients with a high Gleason score and PSA may benefit from additional 18F-FDG PET/CT. ER -