68Ga-PSMA PET/CT Detects the Location and Extent of Primary Prostate Cancer.
We evaluated the accuracy of PET/CT with68Ga-PSMA-HBED-CC-a68Ga-conjugated ligand of human prostate-specific membrane antigen (PSMA)-to localize cancer in the prostate and surrounding tissue at initial diagnosis.


METHODS
Twenty-one patients with biopsy-proven prostate cancer underwent68Ga-PSMA-HBED-CC (68Ga-PSMA) PET/CT at a median of 4 d (range, 0-47 d) before radical prostatectomy. Based on a 6-segment model, the Gleason score and proportion of tumor tissue within each segment (segmental tumor burden, or STB) as determined by histopathology (STBHP) were correlated with SUVmaxand STB as determined by different SUV cutoffs for68Ga-PSMA PET (STBPET1-6). Furthermore, the involvement of seminal vesicles and other extracapsular extension were assessed by histopathology and PET/CT.


RESULTS
Histopathology-positive segments (n = 100 of 126; 79%) demonstrated a significantly higher mean ± SD SUVmax(11.8 ± 7.6) than histopathology-negative segments (4.9 ± 2.9; P < 0.001). Receiver-operating-characteristic analysis revealed an optimal SUVmaxcutoff of 6.5 for discrimination of histopathology-positive segments from histopathology-negative segments (area under the curve, 0.84; P < 0.001), which gave 67% sensitivity, 92% specificity, a 97% positive predictive value, a 42% negative predictive value, and 72% accuracy. STBPET3as determined by (2 × blood SUV) + (2 × SD) correlated best with STBHP(Pearson ρ = 0.68; P < 0.001; mean difference ± SD, 19% ± 15%). PET/CT correctly detected invasion of seminal vesicles (n = 11 of 21 patients; 52%) with 86% accuracy and tumor spread through the capsule (n = 12; 57%) with 71% accuracy.


CONCLUSIONS
68Ga-PSMA PET/CT accurately detected the location and extent of primary prostate cancer. Our preliminary findings warrant further investigation of68Ga-PSMA PET/CT in conjunction with needle biopsy.
Department of Nuclear Medicine, Ludwig-Maximilians-University of Munich, Munich, Germany wolfgang.fendler@med.uni-muenchen.de.
Wolfgang P
WP
Fendler
Department of Nuclear Medicine, Ludwig-Maximilians-University of Munich, Munich, Germany.
Dorothea F
DF
Schmidt
Department of Nuclear Medicine, Ludwig-Maximilians-University of Munich, Munich, Germany.
Vera
V
Wenter
Institute for Clinical Radiology, Ludwig-Maximilians-University of Munich, Munich, Germany.
Kolja M
KM
Thierfelder
Department of Nuclear Medicine, Ludwig-Maximilians-University of Munich, Munich, Germany.
Christian
C
Zach
Department of Urology, Ludwig-Maximilians-University of Munich, Munich, Germany.|Comprehensive Cancer Center, Ludwig-Maximilians-University of Munich, Munich, Germany; and.
Christian
C
Stief
Department of Nuclear Medicine, Ludwig-Maximilians-University of Munich, Munich, Germany.|Comprehensive Cancer Center, Ludwig-Maximilians-University of Munich, Munich, Germany; and.
Peter
P
Bartenstein
Institute of Pathology, Ludwig-Maximilians-University of Munich, Munich, Germany.
Thomas
T
Kirchner
Department of Nuclear Medicine, Ludwig-Maximilians-University of Munich, Munich, Germany.
Franz J
FJ
Gildehaus
Department of Urology, Ludwig-Maximilians-University of Munich, Munich, Germany.|Comprehensive Cancer Center, Ludwig-Maximilians-University of Munich, Munich, Germany; and.
Christian
C
Gratzke
Institute of Pathology, Ludwig-Maximilians-University of Munich, Munich, Germany.
Claudius
C
Faber
D000328:Adult; D000368:Aged; D000465:Algorithms; D004492:Edetic Acid / Q000031:analogs & derivatives; D005709:Gallium Isotopes; D005710:Gallium Radioisotopes; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D008297:Male; D008875:Middle Aged; D009361:Neoplasm Invasiveness; D009842:Oligopeptides; D009942:Organometallic Compounds; D010865:Pilot Projects; D000072078:Positron Emission Tomography Computed Tomography / Q000379:methods*; D011471:Prostatic Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology*; D019275:Radiopharmaceuticals; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D047368:Tumor Burden
D005709:Gallium Isotopes; D005710:Gallium Radioisotopes; D009842:Oligopeptides; D009942:Organometallic Compounds; D019275:Radiopharmaceuticals; C000718244:gallium 68 PSMA-11; D004492:Edetic Acid
PET; PSMA; biopsy; prostate cancer