[18F]fluorocholine PET/CT imaging for the detection of recurrent prostate cancer at PSA relapse:: experience in 100 consecutive patients

Purpose: We evaluated the potential of PET/CT and [F-18] fluoromethylcholine (FCH) in the assessment of suspected recurrence of prostate cancer after treatment. Methods: One hundred consecutive prostate cancer patients with a persistent increase in serum PSA (> 0.1 ng/ml) after radical prostatectomy ( 58 cases), radiotherapy ( 21 cases) or hormonal therapy alone ( 21 cases) were investigated. After injection of 3.7 - 4.07 MBq/kg of FCH, both early ( at < 15 min) and delayed ( at > 60 min) PET/CT scans were performed in 43 patients, delayed PET/CT scans in 53 patients and early PET/CT scans in four patients. Results: Of the 100 patients, 54 ( PSA 0.22 - 511.79 ng/ml) showed positive FCH PET/CT scans. Thirty-seven patients had bone and/or abdominal lymph node uptake, while 17 showed pelvic activity. Malignant disease was confirmed in all but one. Delayed SUVmax of bone metastases was significantly higher (p< 0.0001 by paired t test) than that measured at < 15 min, whereas no differences were observed between early and delayed SUVs of malignant lymph nodes or pelvic disease. Forty-six patients ( PSA 0.12 - 14.3 ng/ml) showed negative FCH PET/CT scans. Of the negative PET/CT scans, 89% were obtained in patients with serum PSA < 4 ng/ml and 87% in patients with a Gleason score < 8. In none of these cases could recurrent tumour be proven clinically during a follow-up of 6 months. Conclusion: FCH PET/CT is not likely to have a significant impact on the care of prostate cancer patients with biochemical recurrence until PSA increases to above 4 ng/ml. However, in selected patients, FCH PET/CT helps to exclude distant metastases when salvage local treatment is intended.