Detection efficacy of PET/CT with 18F-FSU-880 in patients with suspected recurrent prostate cancer: a prospective single-center study

Our objective was to investigate the efficacy of PET/CT with a novel prostate-specific membrane antigen (PSMA)-targeted PET probe, 18F-FSU-880, for detection and localization of recurrent disease in prostate cancer patients in whom recurrence was suspected based on an increase in plasma prostate-specific antigen (PSA) levels after initial treatment.This study was a prospective institutional review board-approved study of 72 patients (age 56-84 years, PSA level 0.22-40.00 ng/ml) with suspected relapse of prostate cancer after primary therapy, including radical prostatectomy (RP) (n = 35) or radiation therapy (RT) (n = 37). Patients underwent PET/CT approximately 1 h and 3 h after injection of 18F-FSU-880 (101.8-380 MBq). The correlation between patient-based detection rate and Gleason score (GS) of the primary tumor and plasma PSA levels at the time of PET/CT was evaluated. Maximum standardized uptake values (SUVmax) of the positive uptakes at 1 h post-injection were compared with those at 3 h post-injection.In total, 51 patients (71%) showed at least one positive PSMA PET result. The PSA-stratified detection rates were 22% (2/9), 36% (4/11), 89% (16/18) and 85% (29/34) for PSA levels of 0.2 to < 0.5, 0.5 to < 1.0, 1.0 to < 2.0 and ≥ 2.0 ng/ml, respectively. The GS-stratified detection rates were 33% (2/6), 67% (16/24), 70% (16/23) and 89% (17/19) for GS 6, 7, 8 and 9, respectively. In lesion-based analysis, 157 positive lesions were detected at 3 h post-injection, 18 in the prostate or prostate bed, 65 in lymph nodes, 71 in the bone and 3 in the lung. Two local recurrences, eight pelvic lymph nodes and one distant lymph node were depicted only at 3 h post-injection. SUV max at 3 h post-injection was significantly higher than SUVmax at 1 h post-injection (p < 0.001).Our preliminary data suggest that 18F-FSU-880 might be a promising new PSMA-targeting tracer for detecting recurrence after initial treatment in patients with prostate cancer.