Purpose: Salvage radiotherapy (SRT) for biochemical recurrence (BCR) following radical prostatectomy (RP) should if possible be added at a prostate--specific antigen (PSA) level of less than 1--2 ng/mL. The value of positron emission tomography combined with computed tomography (PET/CT) at such low PSA values is not defined. The purpose was to determine what proportion of a well--defined cohort of hormone--naïve patients who were candidates for early salvage radiotherapy had 18 F--choline PET/CT findings suggesting metastases.
Materials and methods:Patients with untreated BCR following RP, PSA < 2 ng/mL, and Gleason score ≥ 7 or PSA doubling time ≤ 6 months underwent 18 F--choline PET/CT. Focal choline uptake in lymph nodes or skeletal sites were recorded.Results: PET/CT indicated metastases in 16 (28%) of 58 patients. In five (9%) patients the scans suggested bone metastases and in 11 (19%) the scans suggested regional lymph node metastases only. For patients with PSA levels < 1.0 ng/mL, the PET/CT scans indicated metastic recurrence in 25%.
Conclusions:18 F--choline PET/CT may be valuable for selecting patients with BCR following RP for SRT or experimental treatment of oligometastases, even at low PSA values.