Fusion of Magnetic Resonance Imaging and Real-Time Elastography to Visualize Prostate Cancer: A Prospective Analysis using Whole Mount Sections after Radical Prostatectomy

PURPOSE

To determine whether the fusion of multiparametric magnetic resonance imaging (MRI) with transrectal real-time elastography (RTE) improves the visualization of PCa lesions compared to MRI alone.

MATERIALS AND METHODS

In a prospective setting, 45 patients with biopsy-proven PCa received prostate MRI prior to radical prostatectomy (RP). T2 and diffusion-weighted imaging (T2WI/DW-MRI) and, if applicable, dynamic contrast-enhanced sequences (T2WI/DW/DCE-MRI) were used to perform MRI/RTE fusion. The probability of PCa on MRI was graded according to the PI-RADS score for 12 different prostate sectors per patient. MRI images were fused with RTE to stratify suspicious from non-suspicious sectors. Imaging results were compared to whole mount sections using nonparametrical receiver operating characteristic curves and the area under these curves (AUC).

RESULTS

41 of 45 patients were eligible for final analyses. Histopathology confirmed PCa in 261 (53%) of 492 prostate sectors. MRI alone provided an AUC of 0.62 (T2WI/DW-MRI) and 0.65 (T2WI/DW/DCE-MRI) to predict PCa and was meaningfully enhanced to 0.75 (T2WI/DW-MRI) and 0.74 (T2WI/DW/DCE-MRI) using MRI/RTE fusion. Sole MRI showed a sensitivity and specificity of 57.9% and 61% with the best results for ventral prostate sectors whereas RTE was superior in dorsal and apical sectors. MRI/RTE fusion improved sensitivity and specificity to 65.9% and 75.3%, respectively. Additional use of DCE sequences showed a sensitivity and specificity of 65% and 55.7% for MRI and 72.1% and 66% for MRI/RTE fusion.

CONCLUSION

MRI/RTE fusion provides improved PCa visualization by combining the strength of both imaging techniques in regard to prostate zonal anatomy and thereby might improve future biopsy-guided PCa detection.

[Clinical and histopathological parameters of prostate cancer: influence of anthropometric indices]

BACKGROUND

Adipose tissue is increasingly considered as an endocrinal active organ and may have an influence on the development and progression of prostate cancer. Adverse body fat distribution, considered a risk factor for cardiovascular disease, is not reflected by the body mass index (BMI).

OBJECTIVE

The purpose of this work was to assess anthropometric indices which provide a better estimate of body fat distribution and to evaluate their association with clinical and histopathological parameters of prostate cancer.

PATIENTS AND METHODS

In patients scheduled for radical prostatectomy between March 2011 and March 2013, height, weight, waist circumference (WC) and hip circumference were measured, then the BMI, waist-to-hip ratio (WHR) and waist-to-height ratio (WHtR) were calculated. The relationships between anthropometric measures and indices and clinical and histopathological features of PCA were evaluated with uni- and multivariate analyses.

RESULTS

In 668 patients available for evaluation, obesity rates were 22.8 %, 50.6% and 30.2 % as defined by BMI ≥ 30, WHR ≥ 1 and WHtR ≥ 0.6, respectively. On univariate analysis, WC and WHtR ≥ 0.6 correlated with tumor volume (TV) > 2.1 cm(2) (p < 0.05), respectively. WC and WHtR were independent predictors of a TV ≥ 2.1 cm(2) (p < 0.05) and a WHtR ≥ 0.6 was an independent predictor of a TV ≥ 2.1 cm(2) (p < 0.018, risk ratio 1.506, 95 % confidence interval 1.072-2.115).

CONCLUSION

In general a higher degree of adiposity seems to correlate with a higher tumor volume. Whether anthropometric indices have prognostic impact needs to be clarified during follow-up.

[Value of real-time elastography to guide the systematic prostate biopsy in men with normal digital rectal exam]

The aim of this study was to evaluate whether real-time elastography-guided biopsy in comparison to grey-scale ultrasound improves prostate cancer detection in patients with an unremarkable digital rectal exam.A total of 231 patients suspicious for prostate cancer were prospectively randomised to transrectal real-time elastography- (126) or grey-scale ultrasound (105)-guided biopsy. The peripheral zone was divided into 6 sectors from base, mid-gland to apex. Lesions with reduced elasticity during real-time elastography and hypoechoic areas during grey-scale ultrasound were defined as suspicious for prostate cancer. Prostate biopsy was guided by real-time elastography (RTE) or grey-scale ultrasound (GSU) using a systematic 10-core approach. Suspicious lesions on RTE or GSU in the corresponding randomised group were targeted within each sector. Accuracy of cancer prediction and histopathological cancer detection rates were evaluated and compared between the 2 imaging modalitiesBaseline characteristics of patients undergoing real-time elastography and grey-scale ultrasound, including age, prostate-specific antigen and prostate volume were not significantly different statistically (p>0.05). Overall, prostate cancer was detected in 76 of 231 cases (32.9%). The cancer detection rate was significantly higher (p=0.007) in patients who underwent a biopsy using real-time elastography (40.5%) compared to the grey-scale-guided group of men (23.8%). Sensitivity and specificity to detect prostate cancer in 1 386 prostate sectors was 53.5% and 70.5% for real-time elastography vs. 11.7% and 93.7% for grey-scale ultrasound, respectively.Compared to conventional grey-scale ultrasound, accuracy to detect prostate cancer using a systematic 10-core biopsy approach was significantly improved under the guidance of real-time elastography.

[Complications of radical retropubic prostatectomies based on the Martin criteria]

BACKGROUND

In 2002 the ten Martin criteria were proposed which should be met when reporting complications following surgery. Only a few studies have evaluated complication rates after open retropubic radical prostatectomy using these criteria. In this study we report on complications of open retropubic radical prostatectomy using the standardized Clavien-Dindo reporting methodology.

PATIENTS AND METHODS

The overall complication rate was 28.6% (907 of 3,172). We registered 1,069 medical or surgical complications in 907 patients. Of these, 714 complications were grade I (66.8%), 195 grade II (18.2%), 139 grade III (13%), and 17 grade IV (1.6%), respectively. The mortality rate (grade V) was 0.1% (4 of 3,172). Older age (hazard ratio 1.049, p=0.023) and a performed lymphadenectomy (hazard ratio 1.804, p=0.024) were independent predictors for high-grade complications (grade III or greater) on multivariate analysis.

RESULTS

Between 08/2003 and 06/2010 complications of 3172 consecutive men who underwent open retropubic radical prostatectomy at a single center were recorded prospectively. Complications which occurred within a period of 30 days postoperatively were graded retrospectively according to the Clavien-Dindo classification. Clinical and histopathological risk factors were statistically evaluated for an association with complication grades. All 10 Martin criteria were fulfilled.

CONCLUSIONS

Using the Clavien-Dindo classification as a standardized reporting methodology, we observed an acceptable overall complication rate of 28.6%. In the majority (85% of all complications) lower grade complications occurred. In this series older age and a lymphadenectomy were risk factors for high-grade complications (III-V). A patient's age remains an important factor when considering the indication for radical prostatectomy.