Tumor localization of 16beta-18F-fluoro-5alpha-dihydrotestosterone versus 18F-FDG in patients with progressive, metastatic prostate cancer.
This trial was an initial assessment of the feasibility, in vivo targeting, and biokinetics of 16beta-(18)F-fluoro-5alpha-dihydrotestosterone ((18)F-FDHT) PET in patients with metastatic prostate cancer to assess androgen receptor expression.


METHODS
Seven patients with progressive clinically metastatic prostate cancer underwent (18)F-FDG and (18)F-FDHT PET scans in addition to conventional imaging methods. Three patients had their studies repeated 1 mo later, 2 while on testosterone therapy, and the third after treatment with 17-allylamino-17-demethoxygeldanamycin (17-AAG). High-pressure liquid radiochromatography was used to separate (18)F-FDHT from radiolabeled metabolites. Lesion-by-lesion comparisons between the (18)F-FDHT, (18)F-FDG, and conventional imaging methods were performed.


RESULTS
Metabolism of (18)F-FDHT was rapid, with 80% conversion within 10 min to radiolabeled metabolites that circulated bound to plasma proteins. Tumor uptake was rapid and tumor retention was prolonged. Fifty-nine lesions were identified by conventional imaging methods. (18)F-FDG PET was positive in 57 of 59 lesions (97%), with an average lesion maximum standardized uptake value (SUV(max)) = 5.22. (18)F-FDHT PET was positive in 46 of 59 lesions (78%), with the average positive lesion SUV(max) = 5.28. Treatment with testosterone resulted in diminished (18)F-FDHT uptake at the tumor site.


CONCLUSIONS
(18)F-FDHT localizes to tumor sites in patients with progressive clinically metastatic prostate cancer and may be a promising agent to analyze antigen receptors and their impact on the clinical management of prostate cancer.
Larson
Steven M
SM
Department of Radiology, Memorial Sloan-Kettering Cancer Center, New York, New York 10021, USA. larsons@mskcc.org
Morris
Michael
M
Gunther
Ilonka
I
Beattie
Brad
B
Humm
John L
JL
Akhurst
Timothy A
TA
Finn
Ronald D
RD
Erdi
Yusuf
Y
Pentlow
Keith
K
Dyke
Jon
J
Squire
Olivia
O
Bornmann
William
W
McCarthy
Timothy
T
Welch
Michael
M
Scher
Howard
H
D000368:Aged; D001859:Bone Neoplasms / Q000000981:diagnostic imaging / Q000378:metabolism / Q000556:secondary; D013196:Dihydrotestosterone / Q000031:analogs & derivatives* / Q000493:pharmacokinetics*; D019788:Fluorodeoxyglucose F18 / Q000493:pharmacokinetics*; D006801:Humans; D008297:Male; D008657:Metabolic Clearance Rate; D008875:Middle Aged; D011471:Prostatic Neoplasms / Q000175:diagnosis / Q000000981:diagnostic imaging* / Q000378:metabolism*; D019275:Radiopharmaceuticals / Q000493:pharmacokinetics; D011944:Receptors, Androgen / Q000378:metabolism*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014018:Tissue Distribution; D014055:Tomography, Emission-Computed / Q000379:methods*; D014915:Whole-Body Counting
D019275:Radiopharmaceuticals; D011944:Receptors, Androgen; D013196:Dihydrotestosterone; D019788:Fluorodeoxyglucose F18; C092353:11-fluoro-dihydro-testosterone