Pelvic lymph node dissection for nodal oligometastatic prostate cancer detected by 68Ga-PSMA-positron emission tomography/computerized tomography

BACKGROUNDThe first evaluation of pelvic extended lymph node dissection (pLND) in oligometastatic prostate cancer (PCa) detected by Ga-68-PSMA PET/CT. METHODSRetrospective analysis of 35 PCa patients underwent Ga-68-PSMA PET/CT affected by biochemical recurrence (BCR) after curative treatment (n=23) or before primary therapy of high-risk PCa (n=12). We performed pLND associated with pathologic imaging in 17 men with nodal oligometastatic PCa. RESULTSIndicative lesions for PCa in PET/CT were detected in 91.4% (32 of 35) of patients. Nodal, bone, visceral (pulmonary), and within the prostate suspected disease were detected in 72% (23 of 32), 16% (5 of 32), 6% (2 of 32), and 47% (15 of 32) of patients, respectively. Median serum PSA in patients with pathological radiotracer uptake in recurrent and high-risk PCa patients was 2.9ng/ml (range 0.18-30) and 19.5ng/ml (range 6-90), respectively. The median number of removed lymph nodes with pLND in recurrent and high-risk PCa was 10 (range 4-17) and 12 (range 8-29) per patient and the median number of positive lymph nodes was 1 (range 1-2) and 3 (2-3) per patient, respectively. In total, two false positive and one false-negative lymph node were found. Diagnostic accuracies per nodal lesion in total of 213 removed nodes: sensitivity, 94%; specificity, 99%; positive predictive value (PPV), 89%, and negative predictive value (NPV), 99.5%. After pLND, 53% (9 of 17) of patients received androgen deprivation therapy and/or radiation therapy and hormonal therapy, while 47% (8 of 17) of patients remained free of any post-surgery therapy. Follow-up PSA remained less than 0.2ng/ml in 82% (14 of 17) of patients. After pLND, immediate BCR (PSA never measured less than 0.2ng/ml) in 18% (3 of 17) of patients was recorded. CONCLUSIONSThis represents the first study of pLND in the setting of nodal oligometastatic PCa detected by Ga-68-PSMA PET/CT. The use of Ga-68-PSMA PET/CT could be to improve the accuracy for the detection of nodal micrometastases. These promising findings need validation in larger studies. Prostate 75:1934-1940, 2015. (c) 2015 Wiley Periodicals, Inc.