Comparison of nomograms predicting lymph node invasion in patients undergoing radical prostatectomy for prostate cancer.

Introduction: The aim of this study was to compare the performance of preoperative risk nomograms or detecting lymph node invasion in a cohort of men undergoing radical prostatectomy (RP).

Methods: A retrospective analysis was performed on all men (n = 145) who underwent RP between 2012 and 2015. Preoperative data was inputted to the Memorial Sloan-Kettering Cancer Centre (MSKCC), Partin 2011 and Briganti nomograms and the University of California San Francisco- Centre of the Prostate Risk Assessment tool (UCSF-CAPRA). The risk of lymph node involvement (LNI) was calculated and compared to final histology.

Results: One hundred three (71%) men underwent a lymph node dissection at RP. Ten (9.7%) demonstrated LNI. The median nodal yield was 15 nodes, with no difference between those with LNI and those without (19.5 vs 14.5, p = 0.22).No patient classified as low risk on the UCSF-CAPRA score had evidence of LNI. In patients with LNI, no patient breached the 2% threshold for lymph node dissection (LND) on the MSKCC nomogram; four patients breached the 5% threshold on the Partin tables while three patients breached the 2.5% threshold for the Briganti nomogram.

Conclusion: Nomograms produce useful information regarding risk of disease; however, they often have not been validated on different populations. Risk predictions need to be considered carefully and treatment decisions were made on a patient specific basis.