Oncologic Outcomes of Template Versus Radioguided Salvage Lymph Node Dissection for Node-only Recurrent Prostate Cancer on Prostate-specific Membrane Antigen Positron Emission Tomography Scan: Results from a Multi-institutional Collaboration.

Abstract

In patients treated with salvage lymph node dissection (sLND) for nodal recurrence of prostate cancer, whether radioguided surgery (RGS) might improve oncologic outcomes as compared with template sLND remains unknown. This study included 259 patients who experienced a prostate-specific antigen (PSA) rise and nodal-only recurrence after radical prostatectomy and underwent pelvic sLND at 11 tertiary referral centers between 2012 and 2022. Lymph node recurrence was documented by prostate-specific membrane antigen positron emission tomography scans. The outcomes included biochemical recurrence (BCR) and clinical recurrence (CR) after sLND. The probability of freedom from each outcome was calculated using Kaplan-Meier analyses. A Cox regression analysis was used to test the hypothesis that surgical technique for sLND (template vs RGS) might be associated with oncologic outcomes. Overall, 80 (31%) and 179 (69%) patients received template and radioguided sLND, respectively. PSA level at sLND was higher in the template than in the radioguided group (median: 1.3 vs 0.6 ng/ml; p < 0.0001), whereas the number of positive nodes on final pathology did not differ between the groups (p = 0.13). The first postoperative PSA level was higher in the template than in the radioguided group (median: 0.5 vs 0.1 ng/ml; p < 0.0001). Overall, there were 181 cases of BCR and 76 cases of CR after sLND. The median follow-up for survivors was 21 mo (interquartile range: 7, 36). The 2-yr BCR-free survival rate for patients in the template versus RGS sLND group was 18% (95% confidence interval [CI]: 9%, 29%) versus 30% (95% CI: 22%, 37%). The 2-yr CR-free survival rate for the template versus RGS sLND group was 51% (95% CI: 35%, 65%) versus 73% (95% CI: 65%, 80%). On multivariable analyses, we did not find evidence of a statistically significant difference between the groups with respect to BCR after sLND (p = 0.7), whereas men treated with RGS had a lower risk of CR after sLND than those receiving template sLND (hazard ratio: 0.51; 95% CI: 0.29, 0.92; p < 0.026). Results of the sensitivity analyses were generally consistent with our main findings. Our data suggest that, in men with node-recurrent prostate cancer treated with sLND, RGS may offer important surgical guidance for surgeons, and this may eventually translate into improved oncologic outcomes. Awaiting further evidence on long-term outcomes of RGS, our study represents the most solid comparative data on different techniques for sLND and provides relevant data for counseling patients with node-only recurrent prostate cancer.