Prostate-specific Membrane Antigen-radioguided Surgery in an EMBARK-like Cohort of Patients with Oligorecurrent Hormone-sensitive Prostate Cancer: Delay in Systemic Treatment.

Abstract

We analyzed data for a cohort of 111 patients with EMBARK-like biochemical recurrence (BCR) of prostate cancer (prostate-specific antigen [PSA] doubling time ≤9 mo, PSA ≥1 ng/ml) after radical prostatectomy and localized oligorecurrence on prostate-specific membrane antigen (PSMA)-based imaging. All patients underwent PSMA-radioguided surgery (RGS). At PSMA-RGS, the median PSA was 1.95 ng/ml (interquartile range [IQR] 1.36-3.20) ng/ml and the median PSA doubling time was 4.0 mo (IQR 2.5-5.5). Clavien-Dindo grade >IIIa complications occurred in nine of 111 patients (8.1%). A complete biochemical response (cBR; PSA decline ≤0.2 ng/ml after PSMA-RGS) was observed in 53 patients (47.7%). In the cBR group (equivalent to the treatment suspension criterion in EMBARK), estimated survival rates at 2 yr were 49.9% (95% confidence interval [CI] 37.2-67.1%) for BCR-free survival and 65.2% (95% CI 52.2-81.4%) for treatment-free survival. A relevant proportion of our PSMA-RGS cohort with localized oligorecurrence on PSMA-based imaging fulfilled the EMBARK criteria. PSMA-RGS yielded meaningful biochemical responses that translated to long-lasting treatment-free periods. PATIENT SUMMARY: For some patients with prostate cancer and no evidence of metastasis on conventional imaging but high risk of metastatic progression, modern molecular imaging identifies small cancer deposits that can be removed via targeted surgery. This surgery led to a significant decrease in PSA (prostate-specific antigen) levels, which allowed a longer break from further treatment.