Multicentre Validation of the 2019 Briganti Nomogram: One Threshold Does Not Fit All

Area of Science:

• Urology
• Surgical Oncology
• Prostate Cancer Management

Background:

• The 2019 Briganti nomogram is a key tool for guiding pelvic lymph node dissection (LND) during radical prostatectomy for localized prostate cancer.
• Previous validation exists, but its generalizability across diverse clinical settings is uncertain.

Purpose of the Study:

• To perform a multicenter external validation of the 2019 Briganti nomogram.
• To assess the nomogram's discrimination, calibration, and clinical utility in a real-world setting.
• To evaluate the impact of varying risk thresholds on spared LNDs and missed lymph node invasions (LNIs).

Main Methods:

• Multicenter external validation involving 481 patients from three French academic institutions.
• Assessment of discrimination using the area under the receiver operating characteristics curve (AUC).
• Evaluation of calibration, clinical utility, and decision curve analysis across different centers.

Main Results:

• The overall AUC was 0.733, but performance varied significantly between centers (AUC range: 0.580-0.768).
• Calibration was generally acceptable but showed overestimation of risk in low-prevalence centers.
• At the recommended 7% threshold, spared LNDs ranged from 51% to 76%, with missed LNIs from 0% to 8.9%.

Conclusions:

• Local validation of the Briganti nomogram is crucial before clinical implementation.
• Population-specific threshold adjustments are necessary to optimize LND decisions.
• Individualizing nomogram-based decisions based on local performance and patient risk tolerance is recommended to prevent under- or overtreatment.