560 68Ga-PSMA PET/CT provides accurate staging of lymph node regions prior to lymph node dissection in patients with prostate cancer

Abstract

INTRODUCTION AND OBJECTIVES: 68Ga-PSMA-HBED-CC (68Ga-PSMA) PET/CT has received considerable attention as new diagnostic tool for prostate cancer (PCa) staging. We evaluated the accuracy of 68Ga-PSMA PET/CT for nodal staging prior to lymph node dissection (LND) in patients with PCa. METHODS: 34 patients with histologically proven PCa underwent 68Ga-PSMA PET/CT prior to radical prostatectomy with primary lymph node dissection (pLND; n1⁄420) and PET/CT prior to secondary lymph node dissection (sLND; n1⁄414). Accuracy (ACC) of PET and CT were analyzed separately for staging of the following 71 lymph node (LN) regions: pelvic left (n1⁄430), pelvic right (n1⁄431), presacral (n1⁄43), and paraaortic (n1⁄47). Postoperative histopathology was taken as reference standard. RESULTS: Overall 484 LNs were resected from 71 regions. 132 nodes from 37 regions (52%) showed LN metastases on histopathology. Sensitivity, specificity, positive predictive value, negative predictive value for detection of LN metastases were 84, 82, 84, 82% for PET and 65, 76, 75, 67% for CT. PET was more accurate for nodal staging as compared to CT in both, pLND (88 versus 75%) and sLND (77 versus 65%). On a patient basis PET demonstrated a SE of 91%, PPV of 83%, NPV of 80% for detection of LN metastases. SP was lower (67%); the overall ACC for detection of N stage was 82% on a patient basis. CONCLUSIONS: Our study demonstrates high accuracy of 68Ga-PSMA PET/CT for nodal staging in PCa patients both before primary and secondary LND.