Poor standard mp-MRI and routine biopsy fail to precisely predict intraprostatic tumor localization

Contrast-enhanced ultrasound with dispersion analysis for the localization of prostate cancer: correlation with radical prostatectomy specimens

PURPOSE

To determine the value of two-dimensional (2D) contrast-enhanced ultrasound (CEUS) imaging and the additional value of contrast ultrasound dispersion imaging (CUDI) for the localization of clinically significant prostate cancer (csPCa).

METHODS

In this multicentre study, subjects scheduled for a radical prostatectomy underwent 2D CEUS imaging preoperatively. CUDI maps were generated from the CEUS recordings. Both CEUS recordings and CUDI maps were scored on the likelihood of presenting csPCa (any Gleason ≥ 4 + 3 and Gleason 3 + 4 larger than 0.5 mL) by five observers and compared to radical prostatectomy histopathology. An automated three-dimensional (3D) fusion protocol was used to match imaging with histopathology. Receiver operator curve (ROC) analysis was performed per observer and imaging modality.

RESULTS

133 of 216 (62%) patients were included in the final analysis. Average area under the ROC for all five readers for CEUS, CUDI and the combination was 0.78, 0.79 and 0.78, respectively. This yields a sensitivity and specificity of 81 and 64% for CEUS, 83 and 56% for CUDI and 83 and 55% for the combination. Interobserver agreement for CEUS, CUDI and the combination showed kappa values of 0.20, 0.18 and 0.18 respectively.

CONCLUSION

The sensitivity and specificity of 2D CEUS and CUDI for csPCa localization are moderate. Despite compressing CEUS in one image, CUDI showed a similar performance to 2D CEUS. With a sensitivity of 83% at cutoff point 3, it could become a useful imaging procedure, especially with 4D acquisition, improved quantification and combination with other US imaging techniques such as elastography.

Validation of the current eligibility criteria for focal therapy in men with localized prostate cancer and the role of MRI

PURPOSE

To validate current eligibility criteria for focal therapy (FT) in prostate cancer men undergoing radical prostatectomy (RP) and to assess the role of magnetic resonance imaging (MRI).

METHODS

Retrospective analysis of 217 RP patients (2009-2016) with preoperative MRI (almost all in external institutions) and fulfillment of different FT eligibility criteria: unilateral tumor, clinical tumor stage ≤ cT2a, prostate volume ≤ 60 mL and either biopsy Gleason 3 + 3 or ≤ 3 + 4 and PSA ≤ 10 or ≤ 15 ng/mL. Multivariable logistic regression analyses (MVA) assessed the role of MRI to predict the presence of significant contralateral tumor or extracapsular extension (ECE), including seminal vesicle invasion. To quantify model accuracy, Receiver Operating Characteristics-derived area under the curve (AUC) was used.

RESULTS

Of 217 patients fulfilling widest biopsy criteria and 113 fulfilling additional MRI criteria, 64 (29.7%) and 37 (32.7%) remained eligible for FT according to histopathological results. In MVA, fulfillment of MRI criteria reached independent predictor status for prediction of contralateral tumor but not for ECE. Addition of MRI resulted in AUC gain (57.5-64.6%). Sensitivity, specificity, PPV and NPV for MRI to predict contralateral tumor were: 41.8, 71.6, 70.9 and 42.6%, respectively. Virtually the same results were recorded for Gleason 3 + 3 and/or PSA ≤ 10 ng/mL.

CONCLUSIONS

Patient eligibility criteria for FT using biopsy criteria remained insufficient with respect to contralateral tumor disease. Although, MRI improves accuracy, it cannot safely exclude or minimize chance of significant cancer on contralateral prostate side. To date, stricter eligibility criteria are needed to provide more diagnostic reliability.

From novice to expert: analyzing the learning curve for MRI-transrectal ultrasonography fusion-guided transrectal prostate biopsy

PURPOSE

To investigate the learning curve of a novice in MRI/TRUS software fusion biopsy and to compare his results with the expert standard at our institution.

METHODS

Overall 126 MRI/TRUS fusion-guided transrectal biopsies were performed using an electromagnetic tracking ultrasonography platform. The learning progress of the novice was evaluated comparing his initial 42 procedures (group A) with his following 42 (group B). The institution's expert standard (group C), which was compared to the novice's groups, was defined by the expert's experience of 42 MRI/TRUS fusion biopsies. Primary learning curve parameters were targeted biopsy detection quotient and biopsy time.

RESULTS

Overall detection of prostate cancer was 64% (27/42), 62% (26/42) and 62% (26/42) in groups A, B and C, respectively. The median target biopsy detection quotient significantly increased (p = 0.04) in group B (0.75, interquartile range (IQR) 0.25-1.0) compared to group A. (0.33, IQR 0.2-0.5). Group C revealed a median detection quotient of 0.5 (IQR 0.25-0.76) that did not differ significantly from the novice's groups (p = 0.2). Median biopsy time was significantly higher in group A (45 min, IQR 33-50 min) compared to groups B (25 min, IQR 23-29 min) and C (24 min, IQR 16-46 min) (p < 0.01).

CONCLUSIONS

The present study revealed the individual learning curve of a novice in MRI/TRUS fusion biopsy and demonstrated significant learning progress regarding targeted biopsy detection quotient and biopsy time.

Cost consideration in utilization of multiparametric magnetic resonance imaging in prostate cancer

The screening, evaluation and management of prostate cancer changed significantly in the last decade. The recommendations regarding prostate cancer screening continue to evolve with new revelations about existing data sets and longer followup of landmark trials. Robotics has gained the vast majority of the marketplace for surgically managed prostate cancer in rapid fashion. The need for intervention in low risk prostate cancer has been closely examined and more men are being expectantly managed than ever before. Amidst all these changes, prostate magnetic resonance imaging (MRI) has emerged as a disruptive technology. Through the use of dynamic contrast-enhanced and diffusion weighted series, prostate tumors that were previously not visible have become identifiable and quantifiable. The ability of MRI to improve staging and identification of clinically significant disease has resulted in increased utilization for different aspects of prostate cancer care. The best studied use is in men with a prior negative transrectal ultrasound guided (TRUS) prostate biopsy and the performance characteristics in this role match well with the clinical question raised. The role for MRI in initial biopsy, in pre-surgical planning before prostatectomy and in men on active surveillance is less well defined. A primary concern in the use of MRI is that of cost. MRI units are expensive, both in initial outlay and ongoing use. The availability of MRI varies widely between countries and even within regions of the same country. Different healthcare models have different approaches for allocating the use of expensive resources, including MRI, in times when they are scarce. Prostate MRI can be used at multiple points in the management algorithm of prostate cancer and each implies different cost concerns. In this review we present an overview of current research in cost and cost efficacy for the use of MRI in the management of prostate cancer. By examining what is known and highlighting areas of ongoing research we hope to provide the reader with a solid foundation for understanding these complex, ever-changing issues.