Validation of pre- and postoperative nomograms used to predict the pathological stage and prostate cancer recurrence after radical prostatectomy: a multi-institutional study.

PURPOSE: To validate the preoperative and postoperative predictive tables of Johns Hopkins hospital, Baltimore, Maryland (JHH) and the prostate nomograms of Memorial Sloan Kettering Cancer Center, New York (MSKCC), most commonly used to predict the pathological tumor stage and postoperative freedom from recurrence, in a mixed cohort of Bulgarian prostate cancer patients.
METHODS: Clinical and laboratory data of 282 prostate cancer patients, who underwent radical prostatectomy, were supplied from three different institutions in Bulgaria. Preoperative prostate specific antigen (PSA) values, clinical stage, biopsy Gleason score and the pathological features of the radical prostatectomy specimens were collected from each center and evaluated. Nomogram-predicted probabilities for the presence of unfavorable pathological parameters (extracapsular extension, seminal vesicle invasion/SVI, and lymph node involvement/LNI), and the 5-year freedom from recurrence were compared with actual patient outcomes. Areas under the receiver operating characteristic (ROC) curves (AUC) were determined for each variable to assess the predictive accuracy of the nomograms applied.
RESULTS: The MSKCC prostate cancer nomograms showed superior accuracy for all parameters studied, as compared with the JHH predictive tables. AUC values for organ-confined disease (OCD), SVI and LNI were calculated as 0.763, 0.750, 0.756 and 0.868, 0.787, 0.874 for JHH and MSKCC nomograms, respectively. The AUC values for 5-year freedom from recurrent disease were 0.751, 0.812, 0.813 and 0.894 for pre- and postoperative JHH and MSKCC nomograms, respectively.
CONCLUSION: Despite the potential for heterogeneity in patient selection and management, most predictions demonstrated high concordance with actual observations. All studied nomograms showed reasonable predictive values for the fi nal pathological features, like OCD, SVI and LNI, and for the 5-year freedom from recurrent disease. This multi-institutional study showed that each of the predictive tools studied could be used in Bulgarian patients with comparable accuracy. Compared with the JHH tables, the MSKCC prostate cancer nomograms showed higher predictive accuracy and should therefore be preferred.