V4-07: Early experience of robotic salvage pelvic lymph node dissection in the Ga-68 PSMA PET scanning era
The success of aggressive approaches to biochemical recurrence following radical prostatectomy is dependent on the quality of imaging used to identify disease. Choline-based PET scanning has been the optimum imaging modality to assess this, but it has poor sensitivity at low levels of PSA, is expensive, and is bot widely available. 68Ga-PSMA PET/CT has recently been introduced and shows much promise for the assessment of recurrence following radical prostatectomy. Our aim is to assess the utility of salvage pelvic lymph node dissection in men with biochemical recurrence after radical prostatectomy selected by 68Ga-PSMA PET/CT.
From July 2014 to October 2015 men with biochemical recurrence after radical prostatectomy demonstrating evidence of retroperitoneal or pelvic nodal disease recurrence on 68Ga-PSMA PET/CT treated with salvage lymph node dissection were retrospectively selected for this analysis. Biochemical recurrence was defined as postop PSA ?0.2 ng/ml or rising PSA below this level if leading to the use of salvage therapy. Biochemical response was defined as PSA <0.2 ng/ml at 6 weeks after salvage surgery. </p>
From a total of 296 68Ga-PSMA PET/CT performed at our centre, 14 men met our inclusion criteria. The median age of the cohort was 65(IQR 64-72) years and the median Gleason score at prostatectomy was 8 (IQR 7-9). The median PSA at the time of PSMA PET/CT was 2.1 (IQR 0.46-3.60) ng/ml and the median time between prostatectomy and PSMA PET/CT was 7(IQR 2-11) years. The median number of avid lymph nodes for the series was 1(IQR 1-3). The median nodal yield was 13(IQR 15-22) with 3 (IQR 1-4) nodes being positive for metastatic disease. The median post procedure PSA was 1.39 (IQR 0.29-4.31) ng/ml with one man experiencing biochemical response._x000D_ _x000D_
Despite previous reports about the therapeutic utility of salvage LND in men with BCR after RP with evidence of nodal pathologic uptake on PET/CT scan, our experience with such men selected based on 68Ga-PSMA PET/CT findings has been less encouraging. It is prudent to conclude that the availability of PSMA PET does not warrant omitting PLND in high-risk patients at the time of surgery with a view to perform salvage PLND in PSMA PET/CT positive patients. _x000D_ _x000D_