Introduction: The present study evaluates the potential role of 68Ga-PSMA PET/CT to detect pelvic lymph node metastases in newly diagnosed, treatment-naïve high risk prostate cancer (PCa) patients prior to radical prostatectomy and extended pelvic lymphadenectomy.
Methods: A total of 165 men with newly diagnosed high risk PCa (ISUP grade 4/5, PSA > 20 ng/ml or =cT3a) were included in this retrospective analysis. All men had undergone a transperineal MR fusion biopsy and all men underwent RPE with epLND. Patients with neoadjuvant ADT, TRUS guided biopsies, previous radiation or surgeries in the small pelvis were excluded. Imaging findings and pathohistological findings were correlated and sensitivity, specificity, positive and negative predictive values were calculated. The correlation of clinical and biopsy characteristics with PSMA PET/CT.
Results: The median PSA was 24.5 (6.7-185) ng/ml, the median number of dissected lymph nodes was 21-5 (14-45). A total of 68/165 (41,2%) patients had lymph node metastases (LNM) of which 43 (63.2%) were positive on PSMA-PET/CT whereas 25 (36.8%) LNM were negative on PSMA PET/CT. 97/165 (58.8%) pts had pN0 disease of whom 93 (95.9%) and 3 (4.1%) demonstrated negative and positive PSMA PE/CT findings, resp. n=47 had positive PSMA PET/CT and 40 (85.1%) demonstrated LNM, 7 (14.9%) had pN0 disease. N=118 had negative PSMA PET/CT of which 93 (78.8%) and 25 (21.2%) were true and false negative, resp. Sensitivity was 63.2%, specificity was 97.0%, and positive and negative predictive values were 93.5% and 78,8%, respectively. 3564 lymph nodes were resected, 149 (4.2%) had LNM. 88/149 (59.1%) were detected on PSMA PET/CT and 61 (40.9%) were undetected. On a per lymph node base, sensitivity and specificity were 40.4% and 94.5%, resp; positive and negative predictive values were 59.1% and 97.3%.
Conclusions: PSMA-PET/CT has a high reliability to identify patients with high risk PCA and LNM. If a positive lesion is detected, epLND is mandatory due to high frequency of undetected small LNM. PSMA-PET/CT, is superior to standard imaging and it might replace CT/MRI of the small pelvis.
.jpg)
.jpg)