Purpose: This study aims to evaluate the role of 11C-choline PET/CT in patients with biochemical relapse after radical prostatectomy (RP) showing prostate-specific antigen (PSA) values lower than 0.5 ng/mL.
Methods: We performed 11C-choline PET/CT in 71 consecutive patients previously treated with RP showing PSA values lower than 0.5 ng/mL. 11C-Choline PET/CT was performed following standard procedure. 11C-Choline PET/CT–positive findings were validated by transrectal ultrasonography + biopsy, repeated 11C-choline PET/CT, other conventional imaging modality, and histology.
Results: 11C-Choline PET/CT was true positive in 15/71 (21.1%). 11C-Choline uptake was observed in pelvic lymph nodes (7/71; 9.9%), in the prostatic bed (7/71; 9.9%), and in bone (1/71; 1.4%). Mean PSA, PSA doubling time (PSAdt), and PSA velocity (PSAvel) values ± SD in 11C-choline PET/CT–positive patients was 0.37 ± 0.1 ng/mL, 3.4 ± 2.1 months, and 0.05 ± 0.1 ng/mL/yr, respectively. 11C-Choline PET/CT was false negative in 2 patients and false positive in 1 patient. Among all variables, only PSAdt and the ongoing hormonal treatment were statistically significant in the prediction of a positive 11C-choline PET/CT at multivariate analysis.
Conclusions: 11C-Choline PET/CT could be used early after biochemical failure even if PSA values are very low, preferentially in hormonal resistant patients showing fast PSA kinetics. An early detection of the site of relapse could lead to a personalized and tailored treatment.