Lymph Node Invasion Detection in Prostate Cancer Remains Limited

All evaluated staging modalities for detecting lymph node invasion (LNI) among patients with intermediate-risk prostate cancer undergoing prostatectomy and pelvic lymph node dissection (PLND) exhibited limited sensitivity, according to findings from a study published in BJU International.

Specifically, among 8043 patients with intermediate-risk prostate cancer, 25.8% had an abdominal CT, 5.0% had a PSMA-PET scan, and 1.8% had an abdominal MRI for staging. Furthermore, 29.1%, 6.1%, and 2.0% of patients classified as unfavorable intermediate-risk disease by NCCN guidelines received an abdominal CT, a PSMA-PET scan, or an abdominal MRI, respectively. Among patients classified as having favorable disease, an abdominal CT, a PSMA-PET scan, or an abdominal MRI were received by 20.2%, 3%, and 1.6% of patients.

Regarding sensitivity, the highest was recorded with PSMA-PET (13%), then MRI (8.3%), and then CT (0.9%). Additionally, the negative predictive value (NPV) with the respective staging modalities was 92.5%, 89.5%, and 89.0%. Moreover, the overall accuracy was 92.6%, 88.7%, and 86.5% with each modality, respectively. Among patients with NCCN unfavorable disease, a lower sensitivity and positive predictive value (PPV) were observed.

One independent predictor for LNI included higher ISUP grade group, with groups 2 (OR, 1.95; 95% CI, 1.30-3.03; P <.01) and 3 (OR, 4.65; 95% CI, 3.10-7.24; P <.001) exhibiting a greater probability of LNI vs group 1. Those with stages cT2a (OR, 1.55; 95% CI,1.26-1.90; P <.001) and cT2b disease (OR, 2.73; 95% CI, 2.10-3.51; P <.001) experienced a greater likelihood of LNI vs those with cT1 disease. Additional independent factors for LNI included higher preoperative prostate-specific antigen (PSA; OR, 1.11; 95% CI, 1.09-1.13; P <.001), older age at radical prostatectomy (OR, 1.02; 95% CI, 1.01-1.03; P <.01) and a higher number of positive cores at biopsy (OR, 1.10; 95% CI, 1.07-1.13; P <.001).

Among patients with pN0 vs pN1 disease, the 60-month biochemical recurrence (BCR)-free survival rate was 83.1% vs 52.3% (P <.001). The metastasis-free survival in the respective groups was 97.0% vs 86.2% (P <.001). Additionally, those with suspicious lymph nodes in PSAM-PET prior to radical prostatectomy experienced a 60-month BCR-free survival rate of 45.4% vs 75.1% in those who had unsuspicious PSMA-PET.

“[W]hile PSMA-PET shows promise, the overall performance of all evaluated imaging modalities remains poor in detecting pelvic LNI in patients with [intermediate-risk prostate cancer],” lead author Christopher Kniep, MD, of the Martini-Klinik Prostate Cancer Centre of the University Hospital Hamburg Eppendorf in Hamburg, Germany, wrote in the publication with study coinvestigators. “These results support a more selective and evidence-based approach to imaging, reserving PSMA-PET for specific clinical scenarios, while allowing for skipping staging for most patients with [intermediate-risk prostate cancer].”

Investigators identified patients with intermediate-risk disease who underwent radical prostatectomy with PLND and evaluated the use of multiple staging techniques for assessing pelvic lymph nodes in this group. Techniques included abdominopelvic contrast-enhanced high-dose CT, abdominopelvic contrast-enhanced MRI, or full-body PSMA-PET, with the latter performed with ⁶⁸Ga or ¹⁸F as a tracer. Surgery was delivered via an open retropubic or robot-assisted laparoscopic approach.

The median follow-up of the overall cohort was 48.7 months (IQR, 25.6-73), and the median age was 64 years (IQR, 59-68). Moreover, the median preoperative PSA value was 7.3 ng/mL (IQR, 5.4-10.7), the median number of lymph nodes removed was 14 (IQR, 9-20), and the median number of positive biopsy cores was 4 (IQR, 3-6). Most patients had stage T1c disease (73.6%), biopsy and radical prostatectomy ISUP grade 2 disease (66.2%, 76.5%), and pathological stage 2 disease (64.6%).

Fourfold contingency tables to determine sensitivity, specificity, PPV, and NPV were used to evaluate the performance of staging modalities.

Reference

Kniep C, Maurer T, Hartwieg BF, et al. Diagnostic accuracy and outcomes of lymph node staging in intermediate-risk prostate cancer. BJU Int. Published online January 23, 2026. doi:10.1111/bju.70155