Negative PSMA PET can be used to avoid unnecessary pelvic lymph node dissection in intermediate risk prostate cancer

Abstract

Background: Prostate-specific membrane antigen (PSMA) positron emission tomography (PET) has a high negative predictive value (NPV) in determining lymph node invasion (LNI) in men with intermediate-risk disease undergoing radical prostatectomy (RP) and pelvic lymph node dissection (PLND). We hypothesized that PSMA PET may be used to reduce the number of unnecessary PLND procedures performed. Objective: To assess BCR-free survival of intermediate risk prostate cancer patients with a negative PSMA PET who underwent PLND vs. no PLND. Design, setting, and participants: Within a high-volume center database, we identified patients with Grade Group 2-3 and PSA ≤ 20 ng/ml who had a negative PSMA PET prior to RP between 2016 and 2021. Outcome measurements and statistical analysis: Kaplan–Meier analyses were used to compare BCR-free survival between patients with and without PLND. Results and limitations: Overall, 371 patients were identified. Of those, 333 (90%) underwent RP with PLND, while 38 (10%) had no PLND during RP. Median number of removed lymph nodes in patients with PLND was 16. The NPV of PSMA PET for LNI detection was 90.1%. Median follow-up was 36 months. The median preoperative PSA was 7.8 ng/ml. 59% had biopsy Grade Group 2 and 41% had biopsy Grade Group 3, respectively. BCR-free survival at 36 months after prostatectomy was 78.7% vs. 76.7% (p = 0.8) for patients with vs. without PLND. Main limitation is the absence of long-term oncologic outcomes. Conclusions: In intermediate risk prostate cancer patients, a PLND may be avoided in the presence of a negative PSMA PET.