OBJECTIVE. The purpose of this study was to assess the utility of PET with (2S)-2-[[(1S)-1-carboxy-5-[(6-(18F)fluoranylpyridine-3-carbonyl)amino]pentyl]carbamoylamino]pentanedioic
acid (18F-DCFPyL), a prostate-specific membrane
antigen (PSMA)-targeted radiotracer, in the detection of high-risk localized
prostate cancer as compared with multiparametric MRI (mpMRI). SUBJECTS AND METHODS. This HIPAA-compliant prospective study included 26 consecutive patients with localized high-risk
prostate cancer (median age, 69.5 years [range, 53-81 years]; median
prostate-specific antigen [PSA] level, 18.88 ng/mL [range, 1.03-20.00 ng/mL]) imaged with 18F-DCFPyL PET/CT and mpMRI. Images from PET/CT and mpMRI were evaluated separately, and suspicious areas underwent targeted biopsy. Lesion-based sensitivity and
tumor detection rate were compared for PSMA PET and mpMRI. Standardized uptake value (SUV) and PSMA PET parameters were correlated with histopathology score, and uptake in
tumor was compared with that in nonmalignant tissue. On a patient level, SUV and PSMA
tumor volume were correlated with PSA density. RESULTS. Forty-four
tumors (one in Gleason grade [GG] group 1, 12 in GG group 2, seven in GG group 3, nine in GG group 4, and 15 in GG group 5) were identified at histopathology. Sensitivity and
tumor detection rate of 18F-DCFPyL PET/CT and mpMRI were similar (PET/CT, 90.9% and 80%; mpMRI, 86.4% and 88.4%; p = 0.58/0.17). Total lesion PSMA and PSMA
tumor volume showed a relationship with GG (τ = 0.27 and p = 0.08, τ = 0.30 and p = 0.06, respectively). Maximum SUV in
tumor was significantly higher than that in nonmalignant tissue (p < 0.05).
Tumor burden density moderately correlated with PSA density (r = 0.47, p = 0.01). Five true-positive
tumors identified on 18F-DCFPyL PET/CT were not identified on mpMRI. CONCLUSION. In patients with high-risk
prostate cancer, 18F-DCFPyL PET/CT is highly sensitive in detecting intraprostatic
tumors and can detect
tumors missed on mpMRI. Measured uptake is significantly higher in
tumor tissue, and PSMA-derived
tumor burden is associated with severity of disease.