EAU Biochemical Recurrence Risk Classification and PSA Kinetics Have No Value for Patient Selection in PSMA-Radioguided Surgery (PSMA-RGS) for Oligorecurrent Prostate Cancer

OBJECTIVE: To assess the influence of biochemical recurrence (BCR) risk groups and PSA kinetics on the outcomes of radioguided surgery against prostate-specific membrane antigen (PSMA-RGS). Currently, neither BCR risk group nor PSA doubling time (PSA-DT), or PSA velocity (PSA-V) are actively assigned or relevant for counseling prior to PSMA-RGS.

METHODS: We retrospectively analyzed PSMA-RGS cases for oligorecurrent prostate cancer between 2014 and 2023. BCR risk groups, PSA-DT, and PSA-V were analyzed as predictors for complete biochemical response (cBR, PSA < 0.2 ng/mL), BCR-free, and therapy-free survival (BCRFS, TFS).

RESULTS: Of 374 included patients, only 21/374 (6%) and 201/374 (54%) were classified as low- and high-risk BCR (no group assignment possible in 152/374, 41%). A total of 13/21 (62%) patients with low- and 120/201 (60%) with high-risk BCR achieved cBR (p = 1.0). BCR classification was no predictor for BCRFS (HR:1.61, CI: 0.70-3.71, p = 0.3) or subsequent TFS (HR:1.07, CI: 0.46-2.47, p = 0.9). A total of 47/76 (62%) patients with PSA-DT ≤ 6 mo and 50/84 (60%) with PSA-DT > 6 mo achieved cBR (p = 0.4). PSA-DT was not associated with cBR (OR: 0.99, CI: 0.95-1.03, p = 0.5), BCRFS (HR: 1.00, CI: 0.97-1.03, p = 0.9), or TFS (HR: 1.02, CI: 0.99-1.04, p = 0.2). Consistent negative findings were recorded for PSA-V.

CONCLUSIONS: The BCR risk groups and PSA kinetics do not predict the oncological success of PSMA-RGS performed at low absolute PSA values. Indolent low-risk BCR is rarely treated by PSMA-RGS.