Variations among individual surgeons in the rate of positive surgical margins in radical prostatectomy specimens.

PURPOSE: Cancer at the resection margin (a positive surgical margin) after radical prostatectomy is associated with an increased risk of recurrence even after adjusting for other known risk factors, including pretreatment serum prostate specific antigen (PSA), clinical stage, grade and pathological stage (level of extracapsular extension, seminal vesicle invasion and pelvic lymph node status). Of these prognostic factors only surgical margin status can be influenced by surgical technique. We examined variations in the rate of positive surgical margins among surgeons after controlling for the severity of disease and volume of cases per surgeon. MATERIALS AND METHODS: A total of 4,629 men were treated with radical prostatectomy by 1 of 44 surgeons at 2 large urban centers between 1983 and 2002 for clinical stage T1-T3NxM0 prostate cancer. Patients were excluded if they had previously received androgen deprivation therapy or radiation therapy to the pelvis. Positive surgical margins were defined as cancer at the inked resection margin. Other risk factors analyzed were serum PSA, grade (Gleason sum), extracapsular extension level (none, invasion into the capsule, present [not otherwise specified], focal extracapsular extension or established extracapsular extension), seminal vesicle invasion, pelvic lymph node metastases, surgery date, surgeon and volume of cases per surgeon. RESULTS: For the 26 surgeons who each treated more than 10 patients in the study the rate of positive surgical margins was 10% to 48%. On multivariable analysis higher serum PSA, extracapsular extension level, higher radical prostatectomy Gleason sum, surgery date, surgical volume and surgeon were associated with surgical margin status after controlling for all other clinical and pathological variables. CONCLUSIONS: While the clinical and pathological features of cancer are associated with the risk of a positive margin in radical prostatectomy specimens, the technique used by individual surgeons is also a factor. Lower rates of positive surgical margins for high volume surgeons suggest that experience and careful attention to surgical details, adjusted for the characteristics of the cancer being treated, can decrease positive surgical margin rates and improve cancer control with radical prostatectomy.

A preoperative nomogram identifying decreased risk of positive pelvic lymph nodes in patients with prostate cancer.

PURPOSE: We developed a preoperative nomogram for prediction of lymph node metastases in patients with clinically localized prostate cancer. MATERIALS AND METHODS: The study was a retrospective, nonrandomized analysis of 7,014 patients treated with radical prostatectomy at 6 institutions between 1985 and 2000. Exclusion criteria consisted of preoperative androgen ablation therapy, salvage radical prostatectomy and pretreatment prostate specific antigen (PSA) greater than 50 ng/ml. Preoperative predictors of lymph node metastases consisted of pretreatment PSA, clinical stage (1992 TNM) and biopsy Gleason sum. These predictors were used in logistic regression analysis based nomograms to predict the probability of lymph node metastases. RESULTS: Overall 5,510 patients with complete clinical and pathological information were included in the study. Lymph nodes metastases were present in 206 patients (3.7%). Pretreatment PSA, biopsy Gleason sum, clinical stage and institution represented predictors of lymph node status (p <0.001). Bootstrap corrected predictive accuracy of the 3-variable nomogram (clinical stage, Gleason sum and PSA) was 0.76. Inclusion of a fourth variable, which accounts for institutional differences in lymph node metastases, yielded an area under the receiver operating characteristics curve of 0.78. The negative predictive value of our nomograms was 0.99 when they predicted 3% or less chance of positive lymph nodes. CONCLUSIONS: Using clinical information, we produced 2 calibrated and validated nomograms, which accurately predict pathologically negative lymph nodes in men with localized prostate cancer who are candidates for radical prostatectomy.

Comparisons of nomograms and urologists' predictions in prostate cancer.

When applying nomograms to a clinical setting it is essential to know how their predictions compare with clinicians'. Comparisons exist outside of the prostate cancer literature. We reviewed these comparisons and conducted 2 experiments comparing predictions of clinicians with prostate cancer nomograms. By using Medline, we searched studies from January 1966 to July 1999 that compared human predictions with nomogram predictions. Next, we conducted 2 experiments: (1) 17 urologists were presented with 10 case vignettes and asked to predict the 5-year recurrence-free probabilities for each patient; (2) case presentations of 63 prostate cancer patients (including full clinical histories with complete diagnostic data and surgical findings) were made to a group of 25 clinicians who were asked to predict organ-confined disease. We found 22 published studies comparing human experts with nomograms, greater than half (13 of 22) showed the nomogram performing above the level of the human expert. Our first experiment showed urologist modification of 165 nomogram predictions led to a decrease in prediction accuracy (c-index decreased from.67 to.55, P <.05). In our second experiment, clinician predictions of organ-confined disease were comparable to the nomogram (area under the receiver operating characteristic curve [AUC] 0.78 and 0.79, respectively). A mixed-model suggests the nomogram did not augment clinician prediction accuracy (doctor excess error 1.4%, P =.75, 95% confidence interval [CI]: -10.9% to 8.2%). Our data suggest that nomograms do not seem to diminish predictive accuracy and they may be of significant benefit in certain clinical decision making settings.