Diagnostic value of 18F-FDG positron emission tomography for detection and treatment control of malignant germ cell tumors.
BACKGROUND
The role of positron emission tomography (PET) with 2-[18F]fluoro-2-deoxy-D-glucose ([18F]FDG) is currently under evaluation in urologic oncology. The aim of the present study was to investigate the use of [18F]FDG positron emission tomography ([18F]FDG-PET) in the detection and treatment control of malignant germ cell tumors compared to computed tomography (CT).


METHODS
Thirty-two PET studies and CT scans were carried out in 23 patients with histologically proven germ cell tumors (10 seminomas, 12 non-seminomatous germ cell tumors (NSGCT), 1 unclassified serologic recurrent disease) Lugano stage I-III. The scans were done either after initial diagnosis (n = 21) and/or within 3-45 days after chemotherapy was completed (n = 11). PET and CT were validated either by histology (n = 7) or clinical follow-up of 6-11 months after the last PET study has been performed (n = 16). Sensitivity, specificity, accuracy, positive and negative predictive values were determined for PET and CT. Differences between PET and CT for parameters of diagnostic value were evaluated by chi(2) test.


RESULTS
Although not statistically significant, the sensitivity, accuracy and negative predictive value were higher for PET than for CT with respect to the detection of metastatic infradiaphragmatic and supradiaphragmatic lesions after initial diagnosis. The specificity and positive predictive value of PET and CT were comparable. After chemotherapy, PET was found to be significantly superior in specificity and accuracy compared to CT with respect to infradiaphragmatic lesions (p < 0.05). False-positive PET findings in supradiaphragmatic lesions after chemotherapy occurred in the case of inflammatory processes and resulted in a loss of specificity and accuracy compared to CT (p < 0.05).


CONCLUSIONS
These preliminary results demonstrate [18F]FDG-PET to be a useful diagnostic tool for the initial staging and treatment control in patients with germ cell tumors. Possible advantages compared to CT, however, are as yet not clearly defined. The possibility of false-positive PET findings due to reactive supradiaphragmatic inflammatory processes early after chemotherapy have to be considered.
Tsatalpas
Panagiotis
P
Department of Urology, University of Dresden, Germany.
Beuthien-Baumann
Bettina
B
Kropp
Joachim
J
Manseck
Andreas
A
Tiepolt
Claudia
C
Hakenberg
Oliver W
OW
Burchert
W
W
Franke
Wolf G
WG
Wirth
Manfred P
MP
D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use; D002945:Cisplatin / Q000008:administration & dosage; D019788:Fluorodeoxyglucose F18; D018237:Germinoma / Q000000981:diagnostic imaging* / Q000188:drug therapy; D006801:Humans; D008297:Male; D011237:Predictive Value of Tests; D019275:Radiopharmaceuticals; D012680:Sensitivity and Specificity; D013736:Testicular Neoplasms / Q000000981:diagnostic imaging* / Q000188:drug therapy; D014055:Tomography, Emission-Computed; D014057:Tomography, X-Ray Computed
D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18; D002945:Cisplatin