Validation of pretreatment nomograms for predicting indolent prostate cancer:: Efficacy in contemporary urological practice

Purpose: Many patients diagnosed with low grade and early stage prostate cancer have indolent disease and may not benefit from immediate therapy. In patients referred for biopsy following community, screening we validated the Kattan and Steyerberg nomograms for predicting indolent disease in a contemporary urological practice. Materials and Methods: A total of 296 patients who underwent prostate biopsy and radical prostatectomy at a single institution were identified for nomogram validation. All patients had clinically localized, stage T1c or T2a and biopsy Gleason score 6 prostate cancer. Clinical and biopsy pathological information was compared to surgery pathology results for nomogram validation with indolent disease defined as surgical Gleason score 6 or less, tumor volume less than 0.5 cc and organ confined disease. Nomogram performance was assessed by the ROC curve. Results: Of the patients 27.4% had pathologically indolent disease at prostatectomy. Based on pretreatment variables the Kattan and Steyerberg nomograms were able to predict indolent disease with similar discrimination levels (AUC 0.777 and 0.772, respectively). Conclusions: Two previously described nomograms performed equally well for predicting indolent disease. These data further establish the role of validated nomograms for clinical decision. making for managing screening detected prostate cancer.