Influence of PSA, PSA velocity and PSA doubling time on contrast-enhanced 18F-choline PET/CT detection rate in patients with rising PSA after radical prostatectomy.
OBJECTIVE
To evaluate the accuracy of contrast-enhanced (18)F-choline PET/CT in restaging patients with prostate cancer after radical prostatectomy in relation to PSA, PSA velocity (PSAve) and PSA doubling time (PSAdt).


METHODS
PET/CT was performed in 49 patients (age range 58-87 years) with rising PSA (mean 4.13 ng/ml) who were divided in four groups according to PSA level: ≤1 ng/ml, 1 to ≤2 ng/ml, 2 to ≤4 ng/ml, and >4 ng/ml. PSAve and PSAdt were measured. PET and CT scans were interpreted separately and then together.


RESULTS
PET/CT diagnosed relapse in 33 of the 49 patients (67%). The detection rates were 20%, 55%, 80% and 87% in the PSA groups ≤1, 1 to ≤2, 2 to ≤4 and >4 ng/ml, respectively. PET/CT was positive in 7 of 18 patients (38.9%) with a PSA ≤2 ng/ml, and in 26 of 31 (83.9%) with a PSA >2 ng/ml. PET/CT was positive in 7 of 25 patients (84%) with PSAdt ≤6 months, and in 12 of 24 patients (50%) with PSAdt >6 months, and was positive in 26 of 30 patients (86%) with a PSAve >2 ng/ml per year, and in 7 of 19 patients (36.8%) with PSAve ≤2 ng/ml per year. PET alone was positive in 31 of 49 patients (63.3%), and of these 31 patients, CT was negative in 14 but diagnosed bone lesions in 2 patients in whom PET alone was negative. CT with the administration of intravenous contrast medium did not provide any further information.


CONCLUSIONS
Detection rate of (18)F-choline imaging is closely related to PSA and PSA kinetics. In particular, (18)F-choline PET/CT is recommended in patients with PSA >2 ng/ml, PSAdt ≤6 months and PSAve >2 ng/ml per year. CT is useful for detecting bone metastases that are not (18)F-choline-avid. The use of intravenous contrast agent seems unnecessary.
Department of Biopathology and Diagnostic Imaging, Interventional, University Tor Vergata, Rome, Italy.
Orazio
O
Schillaci
Ferdinando
F
Calabria
Mario
M
Tavolozza
Cristiana Ragano
CR
Caracciolo
Enrico
E
Finazzi Agrò
Roberto
R
Miano
Antonio
A
Orlacchio
Roberta
R
Danieli
Giovanni
G
Simonetti
D000368:Aged; D000369:Aged, 80 and over; D002794:Choline / Q000031:analogs & derivatives*; D003287:Contrast Media; D006801:Humans; D007700:Kinetics; D008297:Male; D008875:Middle Aged; D064847:Multimodal Imaging; D049268:Positron-Emission Tomography; D017430:Prostate-Specific Antigen / Q000097:blood*; D011468:Prostatectomy; D011471:Prostatic Neoplasms / Q000097:blood* / Q000000981:diagnostic imaging* / Q000601:surgery; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed; D051598:Whole Body Imaging
D003287:Contrast Media; C516370:fluoromethylcholine; D017430:Prostate-Specific Antigen; D002794:Choline