68Ga-Prostate-Specific Membrane Antigen Positron Emission Tomography-Computed Tomography-Based Primary Staging and Histological Correlation after Extended Pelvic Lymph Node Dissection in Intermediate-Risk Prostate Cancer.

OBJECTIVE: The objective of this study is to evaluate prostate-specific membrane antigen positron emission tomography-computed tomography (PSMA PET/CT)-based primary staging in exclusively D'Amico intermediate-risk prostate cancer (PCa) patients. PATIENTS AND METHODS: We relied on the Braunschweig institutional database and retrospectively identified D'Amico intermediate-risk PCa patients who were administered to 68Ga-PSMA PET/CT-based primary staging prior to consecutive radical prostatectomy and extended lymph node dissection. Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) for the detection of lymph node metastases were analyzed per-patient (n = 39), per-pelvic side (n = 78), and per-anatomic-region (external iliac artery and vein left/right vs. obturator fossa left/right vs. internal iliac artery left/right) (n = 203), respectively. RESULTS: Sensitivity, specificity, PPV, and NPV per-patient were 20.0, 94.1, 33.3, and 88.9%, respectively. Sensitivity, specificity, PPV, and NPV per-pelvic-side were 16.7, 97.2, 33.3, and 93.3%, respectively. Sensitivity, specificity, PPV, and NPV per-anatomic-region were 16.7, 99.0, 33.3, and 97.5%, respectively. CONCLUSIONS: We recorded high rates of specificity and NPV for 68Ga-PSMA PET/CT-based primary staging in D'Amico intermediate-risk PCa patients. Conversely, the sensitivity and PPV were lower than anticipated. Larger and favorably prospective trials are needed to verify our results and to unravel possible bias from such smaller studies.