Development and External Validation of a Biopsy-Derived Nomogram to Predict Risk of Ipsilateral Extraprostatic Extension.

To develop and externally validate a nomogram that predicts risk of side-specific EPE at time of surgery, using commonly available pre-operative markers.

A consecutive sample of 753 men treated by radical prostatectomy at University Health Network, between 2009 and 2015, was used to develop the nomogram. The validation cohort consisted of 311 men treated by radical prostatectomy at Ottawa Hospital Research Institute, between 1992 and 2014. Study outcome was presence of ipsilateral extraprostatic extension. The association between predictors considered and extraprostatic extension was tested using univariate and multivariate logistic regression analyses. Nomogram predictive accuracy was determined using area under the receiver operating characteristic curve.

The overall rate of extraprostatic extension was 19.8% of all lobes in the developmental cohort and 28.9% in the validation cohort. Significant parameters in the models were age, prostate-specific antigen, and ipsilateral Gleason Score, percent cores positive, and highest core involvement (all p<0.05). The nomogram predicting risk of extraprostatic extension had a predictive accuracy of 0.74 in the external validation cohort.

We developed and externally validated a nomogram that predicts the risk of ipsilateral extraprostatic extension based on commonly used pre-operative markers. This nomogram may be used to assist surgical decision-making prior to radical prostatectomy. This article is protected by copyright. All rights reserved.

BJU international. 2016 Jan 08 [Epub ahead of print]

Rashid Sayyid, Nathan Perlis, Ardalanejaz Ahmad, Andrew Evans, Ants Toi, Michael Horrigan, Antonio Finelli, Alexandre Zlotta, Girish Kulkarni, Robert Hamilton, Christopher Morash, Neil Fleshner

Department of Surgical Oncology, Division of Urology, University Health Network, University of Toronto, Toronto, ON, Canada., Department of Pathology, University Health Network, University of Toronto, Toronto, ON, Canada., Joint Department of Medical Imaging, University Health Network, University of Toronto, Toronto, ON, Canada., Division of Urology, University of Ottawa, Ottawa, Ontario, Canada.