Head-to-Head Comparison of 18F-Prostate-Specific Membrane Antigen-1007 and 18F-Fluorocholine PET/CT in Biochemically Relapsed Prostate Cancer

Purpose of the Report The aim of the study was to prospectively compare performance of 18 F-fluorocholine (FCH) and 18 F-prostate-specific membrane antigen (PSMA)-1007 PET/CT in patients with biochemical relapse (BCR) of prostate cancer and low prostate-specific antigen levels. Methods We prospectively enrolled 40 BCR patients after radical treatment and prostate-specific antigen levels 2.0 ng/mL or less. 18 F-FCH and 18 F-PSMA-1007 PET/CT imaging was performed within a mean interval of 54 ± 21 days. Scans were done 87 ± 10 and 95 ± 12 minutes after injecting 248 ± 35 and 295 ± 14 MBq of 18 F-FCH and 18 F-PSMA-1007, respectively. Rates of negative, equivocal, and positive scan results were compared per patient. Per lesion, findings were grouped as equivocal or highly suggestive of malignancy and then compared for their number, localization (local relapse, lymph nodes, bones), and SUVmax values. Results Positive, equivocal, and negative results were reported in 60%, 27.5%, and 12.5% of 18 F-PSMA-1007 and in 5%, 37.5%, and 57.5% of 18 F-FCH scans, respectively. In 70% of scans, 18 F-PSMA-1007 PET/CT upgraded 18 F-FCH PET/CT results. 18 F-PSMA-1007 scans also showed significantly more lesions (184 vs 63, P = 0.0006). Local relapse, lymph node, and bone lesions accounted, respectively, for 9%, 58%, and 33% of 18 F-PSMA-1007 and 5%, 89%, and 6% 18 F-FCH of PET/CT findings. Highly suspicious lesions accounted for 74% of 18 F-PSMA-1007 and 11% of 18 F-FCH PET/CT findings. In 18 F-PSMA-1007 PET/CT SUVmax values of highly suggestive lesions were significantly higher than in equivocal lesions (median, 3.6 vs 2.5; P < 0.00001). Conclusions In early BCR patients 18 F-PSMA-1007 showed a higher detection rate than 18 F-FCH PET/CT. The former also showed more lesions in total, more highly suggestive lesions and less equivocal lesions.