Oncological Outcomes of Robot-assisted PSMA-guided Salvage Surgery in Recurrent Prostate Cancer: Insights from the Prospective TRACE-I Trial.

BACKGROUND: Prostate-specific membrane antigen (PSMA)-radioguided surgery (RGS) is an emerging technique providing real-time intraoperative guidance. The prospective TRACE-I trial demonstrated that robot-assisted 99mtechnetium-PSMA-Investigation & Surgery-RGS ([99mTc]Tc-PSMA-I&S-RGS) using a DROP-IN gamma probe is feasible and safe in recurrent prostate cancer (PCa). OBJECTIVE: To report the oncological outcmes of a post hoc analysis of the prospective TRACE-I trial cohort. DESIGN, SETTING, AND PARTICIPANTS: TRACE-I prospectively enrolled 30 patients with biochemical recurrence (prostate-specific antigen (PSA) ≥0.2 ng/ml after radical prostatectomy (RP) or ≥2 ng/ml above nadir after radiotherapy (RT) and ≤3 pelvic recurrences (nodal and/or local) on PSMA-positron emission tomography/computed tomography (PET/CT; 2020-2023). INTERVENTION: Patients underwent single-photon emission CT/CT and then robot-assisted PSMA-RGS. OUTCOMES MEASUREMENTS AND STATISTICAL ANALYSIS: Oncological outcomes were biochemical progression (PSA ≥0.2 ng/ml after RP or ≥2 ng/ml above nadir after RT), radiological recurrence on PSMA-PET/CT, and time to salvage therapy. Biochemical progression-free survival (bPFS), distant metastasis-free survival (dMFS), and therapy-free survival (TFS) were analysed using Kaplan-Meier and univariable Cox regression. RESULTS AND LIMITATIONS: Among 30 patients (19 RP, 9 RT, and 2 RP + RT), the median age was 68 yr, and the median PSA at RGS was 1.02 ng/ml (interquartile range, 0.46-2.86), 28 (93%) showed PSA decline after RGS, and 20 (66%) reached PSA <0.2 ng/ml or PSA nadir. The 1- and 2-yr bPFS were 40% and 30%; 2-yr dMFS and TFS were 62% and 58%, respectively. Recurrences were pelvic in 37% and distant in 40%. Limitations include single-centre design and small sample size. CONCLUSIONS: PSMA-RGS in the robotic setting for recurrent PCa shows an early PSA decline in almost all patients. Although biochemical progression after PSMA-RGS is common, PSMA-RGS presents an opportunity to prolong bPFS and TFS in a selection of patients. PATIENT SUMMARY: We updated outcomes from TRACE-I patients with recurrent prostate cancer. We found that PSMA-guided surgery led to PSA declines in most patients and delayed disease progression in some, but careful patient selection is essential.