Diagnostic accuracy and outcomes of lymph node staging in intermediate-risk prostate cancer

To evaluate the diagnostic performance of different staging modalities and oncological outcomes in patients with intermediate-risk (IR) prostate cancer (PCa) undergoing radical prostatectomy (RP) with pelvic lymph node dissection (PLND).

Patients with IR PCa who underwent RP and PLND between 2015 and 2021 were retrospectively analysed. Patients who had received neoadjuvant hormone therapy were excluded. The effectiveness of computed tomography (CT), magnetic resonance imaging (MRI), and prostate-specific membrane antigen-positron emission tomography (PSMA-PET) in detecting lymph node invasion (LNI) was assessed. Kaplan-Meier analysis was used to evaluate biochemical recurrence-free and metastasis-free survival.

Among 8043 patients with IR PCa undergoing RP with PLND, 624 (7.8%) had LNI. PSMA-PET was performed in 400 patients: six true positives, 40 false negatives, 14 false positives, and 340 true negatives. CT was used in 2079 patients: two true positives, 228 false negatives, seven false positives, and 1842 true negatives. MRI was performed in 148 patients: one true positive, 11 false negatives, and 136 true negatives, with no false positives. Sensitivity was highest for PSMA-PET (13%), followed by MRI (8.3%) and CT (0.9%). Negative predictive values were 92.5% for MRI, 89.5% for PSMA-PET, and 89% for CT. Patients with negative PSMA-PET findings had significantly better biochemical recurrence-free and metastasis-free survival than those with suspicious findings on PSMA-PET.

All evaluated staging modalities demonstrated limited sensitivity in detecting LNI in patients with IR PCa, including PSMA-PET. Given the poor diagnostic performance of conventional imaging, such methods may be omitted in this setting. PSMA-PET may still be considered selectively, as it provides modest sensitivity and prognostic value, although its role remains limited.