Open Access

ARTICLE

Nomogram prediction for prostate cancer and aggressive prostate cancer at time of biopsy: utilizing all risk factors and tumor markers for prostate cancer

Robert K. Nam¹, Ants Toi², Laurence H. Klotz¹, John Trachtenberg³, Michael A. S. Jewett³, Andrew Loblaw⁴, Greg R. Pond¹, Marjan Emami¹, Linda Sugar⁵, Joan Sweet⁶, Steven A. Narod⁷

1 Division of Urology, Sunnybrook and Women’s College Health Sciences Centre, Toronto, Ontario, Canada
2 Department of Medical Imaging, University Health Network, Toronto, Ontario, Canada
3 Division of Urology, University Health Network, Toronto, Ontario, Canada
4 Department of Radiation Oncology, Sunnybrook and Women’s College Health Sciences Centre, Toronto, Ontario, Canada
5 Department of Pathology, Sunnybrook and Women’s College Health Sciences Centre, Toronto, Ontario, Canada
6 Department of Pathology, University Health Network, Toronto, Ontario, Canada
7 Department of Public Health Sciences, University of Toronto, Toronto, Ontario, Canada
Address correspondence to Dr. Robert K. Nam, Sunnybrook and Women’s College Health Sciences Centre, 2075 Bayview Avenue, MG-406, Toronto, Ontario M4N 3M5 Canada

Canadian Journal of Urology 2006, 13(Suppl.2), 2-10.

Abstract

Background: There is a large amount of confusion in interpreting prostate specific antigen (PSA) values for prostate cancer. More precise risk assessments for prostate cancer detection are needed for men faced with an abnormal PSA.
Methods: We studied a sample of 2637 men who underwent a prostate biopsy for an abnormal digital rectal exam (DRE) or PSA. Using factors including age, ethnicity, family history of prostate cancer, previous negative biopsy, presence of voiding symptoms, prostate volume, DRE and PSA, we constructed nomograms to predict the probability of prostate cancer at biopsy.
Results: Of the 2637 men, 1282 men (48.6%) had prostate cancer detected. Age, ethnicity, family history of prostate cancer, a previous negative biopsy, prostate volume, DRE and PSA were all significant predictors of prostate cancer. Nomograms were constructed based on these factors to predict the risk of prostate cancer and of aggressive prostate cancer (defined as a Gleason Score ≥7). The positive predictive value varied from 5% to 95% based on the nomograms. The nomograms were validated using bootstrapping methods and the expected and observed proportions were found to be highly concordant.
Conclusions: For men with an abnormal PSA or DRE, the risk for prostate cancer can be accurately estimated using a nomogram based on age, ethnicity, family history of prostate cancer, previous negative biopsy, presence of voiding symptoms, prostate volume, DRE and PSA. This tool will aid physicians and patients in determining the need for prostate biopsy.

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