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68 Ga-PSMA PET/CT Detects the Location and Extent of Primary Prostate Cancer

2016; Society of Nuclear Medicine and Molecular Imaging; Volume: 57; Issue: 11 Linguagem: Inglês

10.2967/jnumed.116.172627

1535-5667

Wolfgang P. Fendler, Dorothea Schmidt, Vera Wenter, Kolja M. Thierfelder, Christian Zach, Christian G. Stief, Peter Bartenstein, Thomas Kirchner, Franz Josef Gildehaus, Christian Gratzke, Claudius Faber,

Prostate Cancer Diagnosis and Treatment

We evaluated the accuracy of PET/CT with 68 Ga-PSMA-HBED-CC—a 68 Ga-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 underwent 68 Ga-PSMA-HBED-CC ( 68 Ga-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 (STB HP ) were correlated with SUV max and STB as determined by different SUV cutoffs for 68 Ga-PSMA PET (STB PET1–6 ). 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 SUV max (11.8 ± 7.6) than histopathology-negative segments (4.9 ± 2.9; P < 0.001). Receiver-operating-characteristic analysis revealed an optimal SUV max cutoff 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. STB PET3 as determined by (2 × blood SUV) + (2 × SD) correlated best with STB HP (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. Conclusion: 68 Ga-PSMA PET/CT accurately detected the location and extent of primary prostate cancer. Our preliminary findings warrant further investigation of 68 Ga-PSMA PET/CT in conjunction with needle biopsy.