Clinical Responses to Prostate-specific Membrane Antigen Radioguided Salvage Lymphadenectomy for Prostate Cancer Recurrence: Results from a Prospective Exploratory Trial

Prostate-specific membrane antigen radioguided salvage pelvic lymph node dissection is feasible but requires continued honing of the technique to optimize oncologic outcomes. Prostate-specific membrane antigen (PSMA) radioguided salvage pelvic lymph node dissection (S-PLND) has emerged as a feasible treatment option for prostate cancer recurrence following initial surgery. This study aims to evaluate the feasibility and short-term outcomes of PSMA radioguided S-PLND. From a prospective trial of 99mTc-PSMA-I&S followed by PSMA radioguided robotic surgery, we evaluated patients treated for node-only recurrence following radical therapy. The primary outcome was serum prostate-specific antigen (PSA) response 3 mo after surgery. Among 14 patients (enrolled from June 2021 to June 2023), the median age was 65 yr. One patient had undergone primary whole gland ultrasound ablation, while the rest received prior prostatectomy. The median (interquartile range) time from primary treatment to PSMA positron emission tomography (PET) was 4.1 (2.9–8.3) yr, and 21 total pelvic targets were noted on PSMA PET: one in eight patients (67%), two in five patients (29%), and three in one patient (7%). Targets were successfully detected intraoperatively and removed in 13/14 (93%) patients. Cancer was noted on histopathology in 90% (19/21) of PSMA PET targets, 94% (17/18) of single-photon emission computed tomography targets, and 82% (14/17) of gamma probe targets. There were no adverse effects due to the radiotracer, and there were no complications after surgery. PSA at 3 mo was