Assessing the Best Surgical Template at Salvage Pelvic Lymph Node Dissection for Nodal Recurrence of Prostate Cancer After Radical Prostatectomy : When Can Bilateral Dissection be Omitted? Results from a Multi-institutional Series

The best surgical template for salvage pelvic lymph node dissection (sLND) in patients with nodal recurrence from prostate cancer (PCa) after radical prostatectomy (RP) is currently unknown. We analyzed data of 189 patients with a unilateral positive positron emission tomography (PET) scan of the pelvic lymph node areas, who were treated with bilateral pelvic sLND after RP at 11 high-volume centers. The primary endpoint was missed contralateral disease at final pathology, defined as lymph node positive for PCa in the side opposite to the positive spot(s) at the PET scan. Overall, 93 (49%) and 96 (51%) patients received a 11C-choline and a 68Ga prostate-specific membrane antigen (PSMA) PET scan, respectively, and 171 (90%) and 18 (10%) men had one and two positive spots, respectively. The rate of missed contralateral PCa was 18% (34/189), with the rates being 17% (29/171) and 28% (5/18) in men with one and two positive spots, respectively. While the rate of contralateral disease did not differ between 68Ga-PSMA and 11C-choline (29% and 27%, respectively) among men with two positive spots, the rate of contralateral PCa was only 6% with 68Ga-PSMA versus 28% with 11C-choline in patients with a single positive spot. This finding was confirmed at multivariable logistic regression analysis predicting missed disease at final pathology after accounting for confounders (odds ratio: 0.24; p = 0.001). However, in men with a single positive spot at 68Ga-PSMA PET/computed tomography, the rate of single confirmed lymph node metastasis at final pathology was only 33%, suggesting the need for extended template even if unilateral dissection is performed. Awaiting confirmatory studies, patients diagnosed with a single positive spot at the 68Ga-PSMA PET scan might be considered for unilateral extended pelvic sLND. Patient summary We assessed the risk of missing contralateral disease in patients with a positron emission tomography (PET) scan suggestive of unilateral nodal recurrence from prostate cancer (PCa) after radical prostatectomy and who were treated with bilateral salvage lymph node dissection (sLND). Variability exists according to the number of positive spots and PET tracer, with the lowest rate of missed PCa in men diagnosed with a single positive spot at a 68Ga prostate-specific membrane antigen PET scan (6%). If replicated, our data suggest that these patients might be considered for unilateral extended pelvic sLND.