Clinical value of ⁶⁸Ga-PSMA-11 PET/CT in the diagnosis of castration-resistant prostate cancer

Objective: To assess the role of ⁶⁸Ga-N, N'-bis(2-hydroxy-5-(carboxyethyl)benzyl) ethylenediamine-N, N'-diacetic acid (HBED-CC)-(Ahx) Lys-CO-Glu(PSMA-11) PET/CT on the detection of metastatic 1esions from castration-resistant prostate cancer (CRPC). Methods: Sixteen patients with CRPC who underwent ⁶⁸Ga-PSMA-11 PET/CT between January 2015 and November 2015 were recruited in this study. Mean age of patients was (72 ± 9) years. The PSA levels were 4-12356 μg/L, Gleason score was 7-10. PET/CT was performed at 1 h postinjection of ⁶⁸Ga-PSMA-11. Patient-based analysis and lesion-based analysis were performed. ROI analysis was used to calculate the tumor uptake (SUV_max). Final diagnosis was based on histopathology and results of other imaging examinations (⁹⁹Tc^m-MDP imaging, MRI). χ² test was used to compare the diagnostic efficiencies of PET and CT. Results: No adverse effects were observed in patients. ⁶⁸Ga-PSMA-11 PET/CT showed moderate physiologic uptake in salivary glands and proximal small intestine, with predominant tracer clearance by the kidneys. All patients were positive on ⁶⁸Ga-PSMA-11 PET/CT. Bone metastasis was found in 16 patients, liver metastasis in 2 patients (5 lesions), and lymph node metastasis in 4 patients (26 lesions). The SUV_max of liver, lymph node and bone metastases were 15.06 ± 2.77, 7.54 ± 5.20, 19.01 ± 16.96, respectively. The diagnostic sensitivity, specificity and accuracy on bone metastasis with ⁶⁸Ga-PSMA-11 PET and CT were 96.30%(52/54) vs 61.11% (33/54), 3/3 vs 1/3, 96.49% (55/57) vs 59.65% (34/57). The sensitivities and accuracies of the two modalities were significantly different(χ² = 19.943, 22.593, both P < 0.01). Conclusions: ⁶⁸Ga-PSMA-11 PET/CT could precisely detect both primary and metastatic lesions of CRPC, suggesting that it is of great value for the clinical management and treatment. (authors)