EURURO Vol. 72 No. 4

632 656

Prostate Cancer
Development and Internal Validation of a Novel Model to
Identify the Candidates for Extended Pelvic Lymph Node
Dissection in Prostate Cancer
Giorgio Gandaglia Nicola Fossati Emanuele Zaffuto Marco Bandini
Paolo Dell’Oglio Carlo Andrea Bravi Giuseppe Fallara Francesco Pellegrino
Luigi Nocera Pierre I. Karakiewicz Zhe Tian Massimo Freschi Rodolfo Montironi
Francesco Montorsi Alberto Briganti
a Unit of Urology/Division of Oncology, URI, IRCCS Ospedale San Raffaele, Milan, Italy; bVita-Salute San Raffaele University, Milan, Italy; c Cancer Prognostics
and Health Outcomes Unit, University of Montreal Health Center, Montreal, Canada; dUnita` Operativa Anatomia Patologica, IRCCS Ospedale San Raffaele,
Milan, Italy; e Section of Pathological Anatomy, Polytechnic University of the Marche Region, School of Medicine, United Hospitals, Ancona, Italy
available at
journal homepage:
Article info
Article history:
Accepted March 30, 2017
Associate Editor:
James Catto
Keywords:
Prostate cancer
Radical prostatectomy
Lymph node invasion
Pelvic lymph node dissection
Nomogram
Abstract
Background: Preoperative assessment of the risk of lymph node invasion (LNI) is mandatory
to identify prostate cancer (PCa) patients who should receive an extended pelvic lymph node
dissection (ePLND).
Objective: To update a nomogram predicting LNI in contemporary PCa patients with detailed
biopsy reports.
Design, setting, and participants: Overall, 681 patients with detailed biopsy information,
evaluated by a high-volume uropathologist, treated with radical prostatectomy and ePLND
between 2011 and 2016 were identified.
Outcome measurements and statistical analysis: A multivariable logistic regression model
predicting LNI was fitted and represented the basis for a coefficient-based nomogram. The
model was evaluated using the receiver operating characteristic-derived area under the curve
(AUC), calibration plot, and decision-curve analyses (DCAs).
Results and limitations: The median number of nodes removed was 16. Overall, 79 (12%)
patients had LNI. A multivariable model that included prostate-specific antigen, clinical stage,
biopsy Gleason grade group, percentage of cores with highest-grade PCa, and percentage of
cores with lower-grade disease represented the basis for the nomogram. After cross valida-
tion, the predictive accuracy of these predictors in our cohort was 90.8% and the DCA
demonstrated improved risk prediction against threshold probabilities of LNI 20%. Using
a cutoff of 7%, 471 (69%) ePLNDs would be spared and LNI would be missed in seven (1.5%)
patients. As compared with the Briganti and Memorial Sloan Kettering Cancer Center
nomograms, the novel model showed higher AUC (90.8% vs 89.5% vs 89.5%), better calibration
characteristics, and a higher net benefit at DCA.
Conclusions: An ePLND should be avoided in patients with detailed biopsy information and a
risk of nodal involvement below 7%, in order to spare approximately 70% ePLNDs at the cost of
missing only 1.5% LNIs.
Patient summary: We developed a novel nomogram to predict lymph node invasion (LNI) in
patients with clinically localized prostate cancer based on detailed biopsy reports. A lymph
node dissection exclusively in men with a risk of LNI > 7% according to this model would
significantly reduce the number of unnecessary pelvic nodal dissections with a risk of missing
only 1.5% of patients with LNI.
# 2017 European Association of Urology. Published by Elsevier B.V. All rights reserved.
* Corresponding author. Unit of Urology/Division of Oncology, URI, IRCCS Ospedale San Raffaele,
Milan, Italy. Tel. +39 0226436923; Fax: +39 0226437286.
E-mail address: (A. Briganti).
0302-2838/# 2017 European Association of Urology. Published by Elsevier B.V. All rights reserved.