[11C]choline PET for the intraprostatic tumor characterization and localization in recurrent prostate cancer after EBRT.

ABSTRACT

AIM: This study focuses on the potential role of [11C]choline positron emission tomography (PET) for the intraprostatic tumor characterization and localization in recurrent prostate cancer after EBRT. METHODS: This retrospective study was conducted in patients who were being followed up after EBRT for histological proven prostate cancer. We selected the patients with a local recurrence by [11C]choline PET/CT fusion. The results of PET were compared with the results of histology and with clinical follow-up. RESULTS: Forty-two patients with a local recurrence suggested by PET were included in this study. According to PET results: of the 42 patients, 15 (36%) had a focal recurrence, 27 (64%) showed a diffuse recurrence. The overall concordance of PET with histology concerning detection of recurrence was 76% (32 patients had positive PET results and positive biopsies). We confirmed the local recurrence as visualized by PET in 37/42 (88%) patients using a composite reference with histology and clinical follow up after local salvage treatment. The concordance of the intraprostatic distribution of the tumor with PET with histology from transrectal prostate biopsies (median biopsies 7, range 4-12) was 47% (7/15) in unilateral cases and 41% (11/27) in bilateral cases. No significant differences were seen between the 2 groups in serum PSA at time of PET (P=0.509) and SUV (P=0.739) using Student's t-test. CONCLUSION: Intraprostatic characterization of recurrent prostate cancer after EBRT with 11C-choline PET is feasible at present but shows a moderate concordance with routine transrectal prostate biopsies. The accuracy is too low for the routine use of this modality in the present scenario.