Early Oncological Outcomes in Patients who Underwent Staging Prostate-specific Membrane Antigen Positron Emission Tomography/Computed Tomography Compared with Conventional Imaging Before Radical Prostatectomy and Extended Pelvic Lymph Node Dissection

Abstract

BACKGROUND AND OBJECTIVE: Prostate-specific membrane antigen (PSMA) positron emission tomography/computed tomography (PET/CT) is increasingly used for primary staging in prostate cancer. Owing to accurate detection of small metastases on PSMA-PET/CT, patient selection for robot-assisted radical prostatectomy (RARP) has likely changed. This study analyzes oncological outcomes in patients undergoing RARP and extended pelvic lymph node dissection (ePLND) after PSMA-PET/CT staging, compared with those without PSMA-PET/CT. METHODS: Patients who underwent staging with PSMA-PET/CT before RARP and ePLND ("PSMA cohort"; 2016-2021) were compared with patients staged without PSMA-PET/CT ("historical cohort"; 2013-2016). Propensity score matching using preoperative variables was performed to limit confounding. As primary outcome measure of biochemical recurrence (BCR)-free survival (BFS) was analyzed, with BCR defined as a prostate specific antigen value of ≥0.2 ng/ml or start of additional therapy after surgery. KEY FINDINGS AND LIMITATIONS: After matching, 880 patients were included (440 in each cohort). The median follow-up was 35 mo (interquartile range 21-60) for the entire cohort. In the PSMA cohort, 126/440 patients (29%) experienced BCR versus 205/440 (47%) in the historical cohort (log-rank test p = 0.032). A multivariable Cox regression analysis showed an independent effect of preoperative PSMA-PET/CT staging on BFS (hazard ratio 0.70, 95% confidence interval 0.55-0.89, p = 0.0030). CONCLUSIONS AND CLINICAL IMPLICATIONS: Patients who underwent staging with PSMA-PET/CT had longer biochemical progression-free survival after RARP and ePLND than those without PSMA-PET/CT. This suggests that PSMA-PET/CT staging alters patient selection for RARP and ePLND, and is associated with improved early oncological outcomes for patients who still undergo surgery. PATIENT SUMMARY: Prostate-specific membrane antigen (PSMA) positron emission tomography/computed tomography (PET/CT) at the diagnosis of prostate cancer leads to better visualization of metastases and therefore better selection of prostate cancer patients for surgery. Patients who underwent a PSMA-PET/CT scan at the time of diagnosis showed improved oncological outcomes, including longer progression-free survival and less prostate-specific antigen persistence after surgery.