Anatomical distribution of disease in pN1 prostate cancer with BCR post‐RP: A PSMA‐PET/CT‐based analysis

Objectives To explore the distribution of metastatic disease in pN1 patients with biochemical recurrence (BCR) assessed by Prostate‐Specific Membrane Antigen‐Positron‐Emission/Computed Tomography (PSMA‐PET/CT). Patients and Methods This multicentre, retrospective cohort study included 130 pN1 PCa patients with BCR (PSA ≥ 0.2 ng/ml) post‐RP with ePLND (2015–2022). All were preoperatively staged as molecular imaging (mi)N0M0 and underwent restaging PSMA‐PET/CT at BCR. Clinical and imaging data were analysed using Mann–Whitney U, chi‐square tests and Cox regression. Results Median time to BCR was 9 months (IQR 3–18). Biochemical persistence (BCP) (PSA ≥ 0.1 ng/ml at first follow‐up) occurred in 66/130 (51%). At restaging PSMA‐PET/CT, median PSA was 0.33 ng/ml (IQR 0.24–0.65). PSMA‐PET/CT identified metastases in 63/130 (48%), with 37/63 (59%) having lymph node metastases (LNMs) limited to the ePLND template – 16/37 (43%) on the ipsilateral side of the positive resected node. Additionally, 26/63 (41%) had disease beyond the nodal template (miM+). Univariate Cox regression identified BCP as a predictor for any PSMA‐PET/CT‐detected recurrence, while a higher ISUP grade group at RP predicted miM+ disease. Conclusion PSMA‐PET/CT identified PSMA‐expressing recurrent disease in nearly half of pN1 PCa patients at early BCR, with about half confined to the pelvis and a quarter beyond the pelvis. These anatomical patterns indicate that PSMA‐PET/CT can inform risk‐adapted salvage strategies, including pelvic radiotherapy for nodal recurrences and systemic treatment when disease extends beyond the pelvis.