Tumour volume and high grade tumour volume are the best predictors of pathologic stage and biochemical recurrence after radical prostatectomy

Multi-institutional external validation of seminal vesicle invasion nomograms: head-to-head comparison of Gallina nomogram versus 2007 Partin tables

PURPOSE

The Partin tables represent one of the most widely used prostate cancer staging tools for seminal vesicle invasion (SVI) prediction. Recently, Gallina et al. reported a novel staging tool for the prediction of SVI that further incorporated the use of the percentage of positive biopsy cores. We performed an external validation of the Gallina et al. nomogram and the 2007 Partin tables in a large, multi-institutional North American cohort of men treated with robotic-assisted radical prostatectomy.

METHODS AND MATERIALS

Clinical and pathologic data were prospectively gathered from 2,606 patients treated with robotic-assisted radical prostatectomy at one of four North American robotic referral centers between 2002 and 2007. Discrimination was quantified with the area under the receiver operating characteristics curve. The calibration compared the predicted and observed SVI rates throughout the entire range of predictions.

RESULTS

At robotic-assisted radical prostatectomy, SVI was recorded in 4.2% of patients. The discriminant properties of the Gallina et al. nomogram resulted in 81% accuracy compared with 78% for the 2007 Partin tables. The Gallina et al. nomogram overestimated the true rate of SVI. Conversely, the Partin tables underestimated the true rate of SVI.

CONCLUSION

The Gallina et al. nomogram offers greater accuracy (81%) than the 2007 Partin tables (78%). However, both tools are associated with calibration limitations that need to be acknowledged and considered before their implementation into clinical practice.

Improved prediction of disease relapse after radical prostatectomy through a panel of preoperative blood-based biomarkers

PURPOSE

The preoperative blood levels of biomarkers may allow accurate identification of patients who are likely to fail radical prostatectomy as a first-line therapy for localized prostate cancer, thereby allowing more efficient delivery of neoadjuvant and adjuvant therapy. The aim of this study was to determine the added value of biomarkers relative to established predictors of biochemical recurrence, such as clinical stage, biopsy Gleason sum, and preoperative prostate-specific antigen.

EXPERIMENTAL DESIGN

The preoperative plasma levels of transforming growth factor-beta1 (TGF-beta1), interleukin-6 (IL-6), soluble IL-6 receptor (sIL-6R), vascular endothelial growth factor (VEGF), vascular cell adhesion molecule-1 (VCAM-1), endoglin, urokinase-type plasminogen activator (uPA), plasminogen activator inhibitor-1, and uPA receptor were measured with the use of commercially available enzyme immunoassays in 423 consecutive patients treated with radical prostatectomy and bilateral lymphadenectomy for clinically localized prostate cancer. Multivariable models were used to explore the gain in the predictive accuracy of the models. This predictive accuracy was quantified by the concordance index statistic and was validated with 200 bootstrap resamples.

RESULTS

In standard multivariable analyses, TGF-beta1 (P < 0.001), sIL-6R (P < 0.001), IL-6 (P < 0.001), VCAM-1 (P < 0.001), VEGF (P = 0.008), endoglin (P = 0.002), and uPA (P < 0.001) were associated with biochemical recurrence. The multivariable model containing standard clinical variables alone had an accuracy of 71.6%. The addition of TGF-beta1, sIL-6R, IL-6, VCAM-1, VEGF, endoglin, and uPA increased the predictive accuracy by 15% to 86.6% (P < 0.001) and showed excellent calibration.

CONCLUSIONS

A nomogram based on these biomarkers improves the accuracy of standard predictive models and could help counsel patients about their risk of biochemical recurrence following radical prostatectomy.

Critical assessment of tools to predict clinically insignificant prostate cancer at radical prostatectomy in contemporary men

BACKGROUND

Overtreatment of prostate cancer (PCa) is a concern, especially in patients who might qualify for the diagnosis of insignificant prostate cancer (IPCa). The ability to identify IPCa prior to definitive therapy was tested.

METHODS

In a cohort of 1132 men a nomogram was developed to predict the probability of IPCa. Predictors consisted of prostate-specific antigen (PSA), clinical stage, biopsy Gleason sum, core cancer length and percentage of positive biopsy cores (percent positive cores). IPCa was defined as organ-confined PCa (OC) with tumor volume (TV) <0.5 cc and without Gleason 4 or 5 patterns. Finally, an external validation of the most accurate IPCa nomogram was performed in the same group.

RESULTS

IPCa was pathologically confirmed in 65 (5.7%) men. The 200 bootstrap-corrected predictive accuracy of the new nomogram was 90% versus 81% for the older nomogram. However, in cutoff-based analyses of patients who were qualified by our and the older nomograms as high probability for IPCa, respectively 63% and 45% harbored aggressive PCa variants at radical prostatectomy (Gleason score 7-10, ECE, SVI, and/or LNI).

CONCLUSIONS

Despite a high accuracy, currently available models for prediction of IPCa are incorrect in 10% to 20% of predictions. The rate of misclassification is even further inflated when specific cutoffs are used. As a consequence, extreme caution is advised when statistical tools are used to assign the diagnosis of IPCa.

Assessment of pathological prostate cancer characteristics in men with favorable biopsy features on predominantly sextant biopsy

BACKGROUND

The rate of insignificant prostate cancer (IPCa) is increasing.

OBJECTIVES

To examine three end points in patients with a single, positive core and no high-grade prostate cancer (PCa) at biopsy, namely (1) rate of clinical IPCa at radical prostatectomy (RP), defined as organ-confined PCa with a Gleason score of 6 or lower and tumor volume<0.5 cc; (2) rate of pathologically unfavorable PCa at RP (Gleason 7-10 or non-organ-confined disease); and (3) ability to predict either insignificant or unfavorable PCa at RP.

DESIGN, SETTING, AND PARTICIPANTS

Retrospective analysis of 209 men with one positive biopsy core showing Gleason 6 or lower.

MEASUREMENTS

: Detailed clinical and RP data were used in multivariable logistic regression models. Their bias-corrected accuracy estimates were quantified using the area under the curve (AUC) method.

RESULTS AND LIMITATIONS

At RP, IPCa was present in 28 patients (13.4%) and pathologically unfavorable PCa, defined as Gleason 7 or higher or non-organ-confined PCa, was reported in 70 (33.5%) of 209 men; when Gleason 8 or higher or non-organ-confined PCa was considered, the proportion fell to 11%. Our multivariable models predicting different categories of pathologically unfavorable PCa at RP had an accuracy rate between 56% and 68% for predicting IPCa at RP versus 65.1% to 66.1% and 61.7% for the IPCa nomograms of Kattan et al and Nakanishi et al, respectively. Our data are not applicable to screening because they originate from a referral population.

CONCLUSIONS

Despite highly favorable biopsy features, between 11% and 33% of men had unfavorable PCa at RP and only a minority (13.4%) had pathologically confirmed IPCa. Neither clinically insignificant nor pathologically unfavorable features could be predicted with sufficient accuracy for clinical decision making.

External validation of a biomarker-based preoperative nomogram predicts biochemical recurrence after radical prostatectomy

PURPOSE

Biomarker signatures currently are used in several malignancies to guide clinical decision making. Recently, preoperative plasma levels of transforming growth factor-beta1 (TGF-beta1) and interleukin-6 soluble receptor (IL6-SR) have improved the accuracy of a clinical nomogram that predicted biochemical recurrence after radical prostatectomy. However, this model was never externally validated. We tested the accuracy of this nomogram in an independent, external cohort.

PATIENTS AND METHODS

Preoperative plasma levels of TGF-beta1 and IL6-SR were measured in 423 consecutive men who underwent radical prostatectomy and bilateral lymphadenectomy and were used, along with preoperative prostate-specific antigen levels, biopsy Gleason sum, and clinical stage to determine nomogram-derived probabilities of biochemical recurrence-free survival at 5 years after radical prostatectomy. The accuracy of predictions was quantified with the area under the curve (AUC) and calibration plots that graphically displayed the nomogram's performance characteristics. The statistical significance of the difference between the biomarker nomogram and a model designed on the basis of clinical variables alone was tested by using the Mantel-Haenszel statistic.

RESULTS

Biochemical recurrence-free survival at 5 years was 77.0% (95% CI, 72.0% to 82.0%). The biomarker-based nomogram was 87.9% accurate versus 71.1% for the nomogram designed on the basis of clinical variables alone (16.8% difference; P < .001). The performance characteristics of the biomarker-based nomogram were superior to those of the clinical nomogram.

CONCLUSION

We confirm that plasma levels of TGF-beta1 and IL6-SR considerably enhance the accuracy of the standard preoperative nomogram for the prediction of biochemical recurrence after radical prostatectomy. This model further refines our ability to identify patients at a high risk of biochemical recurrence after radical prostatectomy.

Early postoperative plasma transforming growth factor-beta1 is a strong predictor of biochemical progression after radical prostatectomy

PURPOSE

Blood levels of transforming growth factor-beta1, interleukin-6 and interleukin-6 soluble receptor have been associated with aggressive primary and metastatic prostate cancer. We hypothesized that patients with increased plasma levels of transforming growth factor-beta1, interleukin-6 and/or interleukin-6 soluble receptor after radical prostatectomy would be more likely to harbor occult metastases, leading to disease progression despite effective local control of disease.

MATERIALS AND METHODS

Plasma transforming growth factor-beta1, interleukin-6 and interleukin-6 soluble receptor were measured 6 to 8 weeks after surgery in 291 consecutive patients treated with radical prostatectomy for clinically localized disease. Discrimination and validation of multivariate Cox regression models targeting time to biochemical progression were used to quantify the added value of these markers to predictive accuracy (concordance index) after internal validation with 200 bootstrap resamples.

RESULTS

On multivariate analysis adjusting for standard postoperative features postoperative plasma transforming growth factor-beta1 was the only biomarker independently associated with biochemical progression (p <0.001). The addition of postoperative transforming growth factor-beta1 improved the accuracy of the standard postoperative model from 78.4% to 84.1%, representing a 5.7% gain (p <0.001). Of patients who experienced biochemical progression postoperative transforming growth factor-beta1 was significantly higher in those with features of aggressive disease progression, ie development of metastasis, prostate specific antigen doubling time less than 10 months and/or failure to respond to local salvage radiation therapy (p <0.001).

CONCLUSIONS

Postoperative interleukin-6 and interleukin-6 soluble receptor have limited clinical usefulness in prostate cancer. In contrast, postoperative plasma transforming growth factor-beta1 measured 6 to 8 weeks after surgery is a strong predictor of biochemical progression, presumably due to an association with early low volume occult metastases that are at the threshold of clinical progression.

Validation of the contemporary epstein criteria for insignificant prostate cancer in European men

OBJECTIVES

The Epstein criteria represent the most widely used scheme for prediction of clinically insignificant prostate cancer (PCa). However, they were never validated in European men. We assessed the rate of unfavorable prostate cancer (Gleason 7-10 or non-organ-confined disease) in a cohort of 366 men who fulfilled the Epstein clinically insignificant PCa criteria.

METHODS

Between 1996 and 2006, 2580 men underwent radical prostatectomy at a single academic European institution. Of those, 366 fulfilled the contemporary Epstein clinically insignificant PCa criteria. Analyses targeted the rate of pathologically unfavorable prostate cancer, defined as either Gleason sum 7-10 or non-organ-confined disease, or a combination of these characteristics in patients with clinically insignificant PCa.

RESULTS

Gleason 7-10 prostate cancer at radical prostatectomy was found in 88 patients (24%) with clinically insignificant PCa. In addition, 30 (34.1%) of the 88 patients harboured non-organ-confined disease. Consequently, the contemporary Epstein criteria for clinically insignificant PCa were inaccurate in 24% of patients.

CONCLUSIONS

The Epstein clinical insignificant PCa criteria may underestimate the true nature of prostate cancer in as many as 24% of European patients. Therefore, caution is advised when treatment decisions are based solely on these criteria.

A comparison of the incidence and location of positive surgical margins in robotic assisted laparoscopic radical prostatectomy and open retropubic radical prostatectomy

PURPOSE

Surgical technique, patient characteristics and method of pathological review may influence surgical margin status. We evaluated the incidence and location of positive surgical margins in 200 sequential robotic assisted laparoscopic radical prostatectomy and 200 sequential open radical retropubic prostatectomy cases.

MATERIALS AND METHODS

From July 2002 until December 2006 a total of 1,747 patients underwent radical prostatectomy at our institution (robotic assisted laparoscopic radical prostatectomy in 1,238, radical retropubic prostatectomy in 509). From these we selected the last 200 consecutive radical retropubic prostatectomies and 200 robotic assisted laparoscopic radical prostatectomies performed before August 2006. Preoperative clinical characteristics including age, clinical stage, prostate specific antigen and Gleason score were evaluated. Postoperatively pathological specimens were assessed for specimen weight, Gleason score, tumor volume, pathological stage and margin status. The incidence and location of positive surgical margins were compared between robotic assisted laparoscopic radical prostatectomy and radical retropubic prostatectomy.

RESULTS

Patients undergoing robotic assisted laparoscopic radical prostatectomy compared to radical retropubic prostatectomy had more favorable tumor characteristics including lower prostate specific antigen, clinical stage and Gleason score. No statistically significant differences were found between groups for prostate volume or tumor volume. However, tumor volume as a percentage of prostate volume was higher among radical retropubic prostatectomy compared to robotic assisted laparoscopic radical prostatectomy cases (17.7% vs 13%, p = 0.001). The overall incidence of positive surgical margins was significantly lower among the robotic assisted laparoscopic radical prostatectomy compared to radical retropubic prostatectomy cases (15% vs 35%, p <0.001). The incidence of positive surgical margins according to pathological stage for robotic assisted laparoscopic radical prostatectomy vs radical retropubic prostatectomy cases was 16 of 171 (9.4%) vs 33 of 137 (24.1%) for pT2 (p <0.001) and 14 of 28 (50%) vs 36 of 60 (60%) for pT3. In both groups the apex was the most common site of positive surgical margins with 52% in the robotic assisted laparoscopic radical prostatectomy group vs 37% in the radical retropubic prostatectomy group (p >0.05).

CONCLUSIONS

In the hands of surgeons experienced in robotic assisted laparoscopic radical prostatectomy and radical retropubic prostatectomy, there was a statistically significant lower positive margin rate for patients undergoing robotic assisted laparoscopic radical prostatectomy. The most common location of a positive surgical margin in robotic assisted laparoscopic radical prostatectomy and radical retropubic prostatectomy cases was at the apex. Patients treated with radical retropubic prostatectomy had higher risk features which may have independently influenced these results. The method of pathological specimen analysis and reporting may account for the higher positive margin rates in both groups compared to some reports.