OBJECTIVE. The purpose of this study was to determine the diagnostic accuracy of 68Ga-labeled prostate-specific membrane antigen 11 (PSMA-11) PET for disease detection in patients with prostate cancer who have biochemically recurrent disease after radiation therapy or prostatectomy. SUBJECTS AND METHODS. One hundred fifty patients underwent 68Ga-PSMA-11 PET/CT or PET/MRI, and the images were interpreted by two blinded board-certified radiologists. Each reader evaluated for the presence or absence of PSMA-positive disease within the prostate bed, pelvic lymph nodes, bones, and soft tissues (extrapelvic lymph nodes and visceral structures). The presence or absence of disease was confirmed by histopathologic analysis if available. For patients who did not have pathologic analysis, a composite of imaging and clinical follow-up was used as the reference standard. RESULTS. The median prostate-specific antigen level was 2.1 ng/mL. Forty-three patients had pathologic correlation, and for 29 patients a composite of imaging and follow-up was used to determine the presence or absence of disease. With substantial to almost perfect interreader reliability by region (κ = 0.78-0.87), 68Ga-PSMA-11 PET had high sensitivity per region (up to 100%) and per patient (up to 89.8%). It also had high positive predictive value per region (up to 100%) and per patient (up to 91.5%). Sensitivity was highest for bone metastases and lowest for soft-tissue metastases. Positive predictive value was highest for bone metastases and lowest for prostate bed recurrence. CONCLUSION. Gallium-68-labeled PSMA-11 PET is sensitive for prostate cancer metastases in patients with biochemically recurrent prostate cancer. It has high positive predictive value and substantial to almost perfect interrater reliability.
Keywords: PET/CT; PET/MRI; PMSA; prostate cancer; prostate-specific membrane antigen.