Importance of Gleason score on 18F-choline PET/CT findings in patients with biochemical relapse of prostate cancer disease (PSA<1.0 ng/ml).

86 Background: Not all tumors show significant increase of metabolic activity on 18F-FDG PET/CT imaging. This is particularly true for prostate cancer, neuroendocrine tumors and hepatic tumors. As a component of cell membrane phospholipids, choline is an excellent biomarker for the malignant transformation and increased proliferation of cells. 18F-choline (18F-FCH) PET/CT is a nuclear medicine procedure that has greater sensitivity and accuracy than 18F-FDG PET/CT to detect prostate malignancy: sensitivity 73% vs. 31% and accuracy 67% vs. 53%, respectively. The efficiency of FCH to detect prostate cancer disease before and after treatment is related to the PSA levels. Evaluation of recurrent disease with 18F-FCH PET/CT imaging in patients with prostate cancer disease is becoming a routine procedure. Purpose: To investigate the role of Gleason score (GS), as a marker of proliferation, on 18F-FCH PET/CT findings in patients with biochemical relapse of prostate cancer disease defined as increased level of prostate specific antigen (PSA). Methods: 140 patients with biochemical relapse (PSA<1.0 ng/ml) underwent 18F-FCH PET/CT scan after treatment: radical prostatectomy, radiotherapy, hormonal therapy alone or combined treatment. Results: 18F-FCH PET/CT detected prostate cancer recurrence in 97% of patients with GS>7, 82% of patients with GS=7 and 63% of patients with GS<7. All patients had PSA between 0.2 and 1.0 ng/ml. Out of 140 patients 43% had recurrence in prostatic bed and 57% patients had local metastasis. Conclusions: Prostate cancer proliferation defined as Gleason score, influence 18F-FCH PET/CT findings in patients with biochemical relapse of prostate cancer disease at any PSA level.