(18)F-JK-PSMA-7 PET/CT for staging intermediate- or high-risk prostate cancer patients before radical prostatectomy: a pilot study

BACKGROUND: Positron emission tomography/computed tomography (PET/CT) using radiotracers that bind to the prostate-specific membrane antigen (PSMA) is mainly used in biochemical recurring prostate cancer. The aim of our study was to assess the usefulness of (18)F-JK-PSMA-7 PET/CT for local and nodal staging in patients with intermediate- and high-risk prostate cancer (PCa) prior to radical prostatectomy, as compared to conventional imaging techniques. METHODS: We enrolled a total of 10 patients with intermediate- and high-risk PCa diagnosed by multiparametric-MRI followed by systematic and targeted biopsies, eligible for radical prostatectomy with extended lymph node dissection. Clinical team was blind to the results of the pre-surgery (18)F-JK-PSMA-7 PET/CT at times of clinical decision and surgery. One month post-surgery, 18F-JK-PSMA-7 PET/CT was repeated and the results of both scans were unblinded. A third (18)F-JK-PSMA-7 PET/CT could be acquired at a later time point depending on PSA progression. RESULTS: All pre-surgery (18)F-JK-PSMA-7 PET/CT was positive in the prostatic region, while MRI was negative in the prostate in one patient. We also detected positive pelvic lymph nodes in two patients (one high-risk, one intermediate-risk PCa) on pre-surgery and post-surgery (18)F-JK-PSMA-7 PET/CT. No positive pelvic lymph nodes were reported on pre-surgical CT and MRI. (18)F-JK-PSMA-7 PET/CT detected bladder involvement in one patient and seminal vesicles involvement in two patients; this malignant extension was undetected by the conventional imaging techniques. SUVmax in prostate lesions had an average value of 11.51 (range 6.90–21.49). SUVmean in prostate lesions had an average value of 7.59 (range 5.26–14.02). CONCLUSION: This pilot study indicates that pre-surgery (18)F-JK-PSMA-7 PET/CT provides valuable information in intermediate- and high-risk PCa, for surgery planning with curative intent.