18F-FACBC Compared With 11C-Choline PET/CT in Patients With Biochemical Relapse After Radical Prostatectomy: A Prospective Study in 28 Patients

IntroductionThe aim of our study was to compare the detection rate of anti-3-18F-FACBC PET/CT in comparison with 11C-choline PET/CT in the evaluation of disease recurrence of PCa after radical prostatectomy.Patients and MethodsTwenty-eight consecutive patients with biochemical relapse after radical prostatectomy were submitted to anti-3-18F-FACBC PET/CT and 11C-choline PET/CT to evaluate the site of disease recurrence. Androgen deprivation therapy was avoided in all cases. The primary end point was the overall detection rate of the 2 radiotracers. A patient-based analysis and a lesion-based analysis was performed. The target to background ratio (TBR) of each lesion was reported.ResultsAt the time of PET scan, mean age was 67 years and mean prostate specific antigen (PSA) relapse was 2.9 ng/mL (range: 0.2-14.6). In patient-based analyses, 11C-choline PET/CT was positive in 5 patients and negative in 23 (detection rate = 17.8%) and anti-3-18F-FACBC PET/CT was positive in 10 patients and negative in 18 (detection rate = 35.7%). All lesions that were positive using 11C-choline were positive using anti-3-18F-FACBC PET/CT but with the latter radiotracer, 11 (61.1%) additional tumors were identified including 5 (17.8%) additional patients. The TBR of anti-3-18F-FACBC was greater than 11C-choline in 15 of 18 lesions, confirming a better image quality and contrast.ConclusionThis preliminary study demonstrated that the detection rate of anti-3-18F-FACBC PET/CT is greater in comparison with 11C-choline, with approximately 20% of additional patients and approximately 60% additional lesions detected. Further studies, however, are required to assess the exact added value of this new tracer.