PSMA-PET and micro-ultrasound potential in the diagnostic pathway of prostate cancer

To compare the diagnostic performance of ⁶⁸Ga-PSMA PET/TC with PRI-MUS (prostate risk identification using micro-ultrasound) in the primary diagnosis of prostate cancer (PCa).

From September till December 2018, we prospectively enrolled 25 candidates to ⁶⁸Ga-PSMA PET/TRUS (transrectal ultrasound) fusion biopsy and compared them with PRI-MUS. This included patients with persistently elevated PSA and/or PHI (prostate health index) suspicious for PCa, negative digital rectal examination, with either negative or contraindication to mpMRI, and at least one negative biopsy. The diagnostic performance of the two modalities was calculated based on pathology results.

Overall, 20 patients were addressed to ⁶⁸Ga-PSMA PET/TRUS fusion biopsy. Mean SUVmax and SUVratio for PCa lesions resulted significantly higher than in benign lesions (p = 0.041 and 0.011, respectively). Using optimal cut-off points, ⁶⁸Ga-PSMA PET/CT demonstrated an overall accuracy of 83% for SUVmax ≥ 5.4 and 94% for SUVratio ≥ 2.2 in the detection of clinically significant PCa (GS ≥ 7). On counterpart, PRI-MUS results were: score 3 in nine patients (45%), score 4 in ten patients (50%), and one patient with score 5. PRI-MUS score 4 and 5 demonstrated an overall accuracy of 61% in detecting clinically significant PCa.

In this highly-selected patient population, in comparison to PRI-MUS, ⁶⁸Ga-PSMA PET/CT shows a higher diagnostic performance.