18F-Fluoroethylcholine PET/CT identifies lymph node metastasis in patients with prostate-specific antigen failure after radical prostatectomy but underestimates its extent.
BACKGROUND
The detection of lymph node metastases (LNMs) is one of the biggest challenges in imaging in urology.


OBJECTIVE
To evaluate the accuracy of combined 18F-fluoroethylcholine (FEC) positron emission tomography (PET)/computed tomography (CT) in the detection of LNMs in prostate cancer (PCa) patients with rising prostate-specific antigen (PSA) level after radical prostatectomy.


METHODS
From June 2005 until November 2011, 56 PCa patients with biochemical recurrence after radical prostatectomy underwent bilateral pelvic and/or retroperitoneal lymphadenectomy based on a positive 18F-FEC PET/CT scan.


METHODS
The findings of PET/CT were compared with the histologic results.


CONCLUSIONS
Median PSA value at the time of 18F-FEC PET/CT analysis was 6.0 ng/ml (interquartile range: 1.7-9.4 ng/ml). In 48 of 56 (85.7%) patients with positive 18F-FEC PET/CT findings, histologic examination confirmed the presence of PCa LNMs. Of 1149 lymph nodes that were removed and histologically evaluated, 282 (24.5%) harbored metastasis. The mean number of lymph nodes removed per surgical procedure was 21 (standard deviation: ± 18.3). A lesion-based analysis yielded 18F-FEC PET/CT sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of 39.7%, 95.8%, 75.7%, and 83.0%, respectively. A site-based analysis yielded sensitivity, specificity, PPV, and NPV of 68.4%, 73.3%, 81.3%, and 57.9%, respectively. Patients with negative PET/CT did not undergo surgery, thus sensitivity, specificity, and negative predictive value on a patient basis could not be calculated.


CONCLUSIONS
A positive 18F-FEC PET/CT result correctly predicted the presence of LNM in the majority of PCa patients with biochemical failure after radical prostatectomy but did not allow for localization of all metastatic lymph nodes and therefore was not adequately accurate for the precise estimation of extent of nodal recurrence in these patients.
Department of Urology, Ludwig-Maximilians-University, Klinikum Grosshadern, Munich, Germany. Derya.Tilki@med.uni-muenchen.de
Derya
D
Tilki
Oliver
O
Reich
Anno
A
Graser
Marcus
M
Hacker
Jürgen
J
Silchinger
Armin J
AJ
Becker
Wael
W
Khoder
Peter
P
Bartenstein
Christian G
CG
Stief
Wolfgang
W
Loidl
Michael
M
Seitz
D000368:Aged; D002794:Choline / Q000031:analogs & derivatives*; D018450:Disease Progression; D006801:Humans; D007610:Kallikreins / Q000097:blood*; D008197:Lymph Node Excision; D008198:Lymph Nodes / Q000000981:diagnostic imaging* / Q000473:pathology / Q000601:surgery; D008207:Lymphatic Metastasis; D008297:Male; D008875:Middle Aged; D064847:Multimodal Imaging; D049268:Positron-Emission Tomography; D011237:Predictive Value of Tests; D017430:Prostate-Specific Antigen / Q000097:blood*; D011468:Prostatectomy / Q000009:adverse effects; D011471:Prostatic Neoplasms / Q000097:blood / Q000000981:diagnostic imaging* / Q000556:secondary / Q000601:surgery*; D019275:Radiopharmaceuticals; D012086:Reoperation; D012189:Retrospective Studies; D013997:Time Factors; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome; D015854:Up-Regulation; D051598:Whole Body Imaging
D019275:Radiopharmaceuticals; C448902:fluoroethylcholine; C549870:KLK3 protein, human; D007610:Kallikreins; D017430:Prostate-Specific Antigen; D002794:Choline