Ga-PSMA Positron Emission Tomography/Computed Tomography Provides Accurate Staging of Lymph Node Regions Prior to Lymph Node Dissection in Patients with Prostate Cancer.

We evaluated the accuracy of Ga-prostate-specific membrane antigen-HBED-CC (Ga-PSMA) positron emission tomography/computed tomography (PET/CT) for nodal staging prior to lymph node dissection (LND) in patients with prostate cancer (PCa). Thirty-four patients with histologically proven PCa underwent Ga-PSMA-HBED-CC PET/CT prior to radical prostatectomy with primary LND (pLND; n=20) and PET/CT prior to secondary LND (sLND; n=14). Accuracy of PET and CT were analysed separately for staging of the following 71 lymph node (LN) regions: pelvic left (n=30), pelvic right (n=31), presacral (n=3), and para-aortic (n=7). Postoperative histopathology was taken as a reference standard. Thirty-seven of 71 (52%) regions showed LN metastases on histopathology. Sensitivity, specificity, positive predictive value, and negative predictive value for detection of LN metastases were 84%, 82%, 84%, and 82% for PET criteria and 65%, 76%, 75%, and 67% for CT criteria. PET was more accurate for nodal staging compared with CT both at pLND (88% vs 75%) and sLND (77% vs 65%). Overall, Ga-PSMA PET/CT provides accurate nodal staging prior to pLND and sLND for PCa. PATIENT SUMMARY: Ga-PSMA positron emission tomography/computed tomography is accurate in detecting tumour spread to lymph nodes before patients undergo surgery for prostate cancer.