Single Lesion on Prostate-specific Membrane Antigen-ligand Positron Emission Tomography and Low Prostate-specific Antigen Are Prognostic Factors for a Favorable Biochemical Response to Prostate-specific Membrane Antigen-targeted Radioguided Surgery in Recurrent Prostate Cancer

Background: Prostate-specific membrane antigen (PSMA)-ligand positron emission tomography (PET) allows detection of metastatic prostate cancer (PC) lesions at low prostate-specific antigen (PSA) values. To facilitate their intraoperative detection during salvage surgery, we recently introduced PSMA-targeted radioguided surgery (RGS).

Objective: To describe the outcome of a large cohort of patients treated with PSMA-targeted RGS and to establish prognostic factors.

Design, setting, and participants: A total of 121 consecutive patients with recurrent PC as defined by PSMA-ligand PET (median PSA: 1.13ng/ml) underwent PSMA-targeted RGS.

Outcome measurements and statistical analysis: The frequency of a complete biochemical response (cBR; PSA <0.2ng/ml) without additional treatment and the duration of biochemical recurrence-free survival (bRFS, time from PSMA-targeted RGS with PSA <0.2ng/ml without further treatment) were evaluated and correlated with preoperatively available clinical variables.

Results and limitations: In almost all patients (120/121, 99%) metastatic tissue could be removed. A cBR was achieved in 77 patients (66%). The chance of cBR was highest in patients with both low preoperative PSA and a single lesion (38/45: 84%). Median bRFS was 6.4mo in the whole patient cohort and 19.8mo for patients with cBR. Significantly longer median bRFS was observed in patients with a low preoperative PSA value (p=0.004, hazard ratio 1.48, 95% confidence interval 1.13-1.93) and with a single lesion in preoperative PSMA-ligand PET (14.0 vs 2.5mo, p=0.002).

Conclusions: PSMA-targeted RGS leads to a remarkable interval of bRFS in a subset of patients. The frequency of cBR and the duration of bRFS were highest in patients with a low preoperative PSA value and a single lesion on PSMA-ligand PET.

Patient summary: Prostate-specific membrane antigen radioguided surgery delays disease progression in selected patients with recurrent prostate cancer after radical prostatectomy. Patients with a single lesion of recurrence and a low prostate-specific antigen value had the best outcome.