Introduction:

PSMA-PET/CT is increasingly used to stage high-risk prostate cancer, but its limited sensitivity for lymph node involvement (LNI) raises questions about its role in surgical planning and prognosis. We aimed to measure the sensitivity of PSMA-PET/CT for detecting LNI in patients undergoing radical prostatectomy (RP) and extended pelvic lymph node dissection (PLND) at a high-volume center, and to evaluate whether PSMA nodal status independently predicts postoperative oncologic outcomes.

Methods:

We identified 79 consecutive patients with clinically localized or locoregional prostate cancer who underwent preoperative PSMA-PET/CT followed by RP between 2021 and 2024 and had pathologically confirmed LNI (pN1) on PLND. We evaluated sensitivity of PSMA-PET/CT for detecting pN1 disease. The association between PSMA-PET/CT and both biochemical recurrence (BCR) and radiographic recurrence was evaluated using Cox regression models adjusted for baseline recurrence risk. Recurrence sites were classified as periprostatic, in-template, or out-of-template relative to the surgical dissection field.

Results:

PSMA-PET/CT detected LNI in 24 of 79 patients, a sensitivity of 30% (95% CI 21, 42%). PSMA-positive nodal disease (cN1) was significantly associated with BCR (HR 2.34, 95% CI 1.26, 4.36; p=0.009) and radiographic recurrence (HR 4.23; 95% CI 1.86, 9.58; p<0.001). The one-year risk of BCR was close to 90% for cN1. Median metastatic focus size was larger in cN1 vs cN0 patients (1.1 vs 0.3 cm; p<0.001). Among 25 patients with locoregional-only recurrence, 76% occurred outside the surgical template. Limitations include relatively short follow-up.

Conclusion:

Due to low sensitivity, PLND remains essential, regardless of PSMA-PET/CT findings. However, PSMA-avid nodal disease indicates almost inevitable recurrence and radiographic progression, supporting treatment intensification.

Funding: This work was supported by the Sidney Kimmel Center for Prostate and Urologic Cancers at MSKCC and NIH/NCI grants P30CA008748 and P50CA092629.