Application of Multiple Ultrasonic Techniques in the Diagnosis of Prostate Cancer

Methods for diagnosing prostate cancer (PCa) are developing in the direction of imaging. Advanced ultrasound examination modes include micro-Doppler, computerized-transrectal ultrasound, elastography, contrast-enhanced ultrasound and microultrasound. When two or more of these modes are used in PCa diagnosis, the combined technique is called multiparameter ultrasound (mp-US). Mp-US provides complementary information to multiparameter magnetic resonance imaging (mp-MRI) for diagnosing PCa. At present, no study has attempted to combine the characteristics of different ultrasound modes with advanced classification systems similar to the PIRADS system in mpMRI for the diagnosis of PCa. As an imaging method, mp-US has great potential in the diagnosis of PCa.

Brachytherapy focal dose escalation using ultrasound based tissue characterization by patients with non-metastatic prostate cancer: Five-year results from single-center phase 2 trial

PURPOSE

This prospective trial investigates side effects and efficacy of focal dose escalation with brachytherapy for patients with prostate cancer.

METHODS AND MATERIALS

In the Phase II, monocentric prospective trial 101 patients with low-/intermediate- and high-risk prostate cancer were enrolled between 2011 and 2013. Patients received either PDR-/HDR-brachytherapy alone with 86-90 Gy (EQD2, α/β = 3 Gy) or PDR-/HDR-brachytherapy as boost after external beam radiation therapy up to a total dose of 91-96 Gy (EQD2, α/β = 3 Gy). Taking place brachytherapy all patients received the simultaneous integrated focal boost to the intra-prostatic tumor lesions visible in computer-aided ultrasonography (HistoScanning™) - up to a total dose of 108-119 Gy (EQD2, α/β = 3 Gy). The primary endpoint was toxicity. Secondary endpoints were cumulative freedom from local recurrence, PSA-free survival, distant metastases-free survival, and overall survival. This trial is registered with ClinicalTrials.gov, number NCT01409876.

RESULTS

Median follow-up was 65 months. Late toxicity was generally low with only four patients scoring urinary grade 3 toxicity (4/101, 4%). Occurrence of any grade of late rectal toxicities was very low. We did not register any grade ≥2 of late rectal toxicities. The cumulative 5 years local recurrence rate (LRR) for all patients was 1%. Five years- biochemical disease-free survival estimates according Kaplan-Meier were 98,1% and 81,3% for low-/intermediate-risk and high-risk patients, respectively. Five years metastases-free survival estimates according Kaplan-Meier were 98,0% and 83,3% for all patients, low-/intermediate-risk and high-risk patients, respectively.

CONCLUSIONS

The 5 years-results from this Phase II Trial show that focal dose escalation with computer-aided ultrasonography and brachytherapy for patients with non-metastatic prostate cancer is safe and effective.

Multiparametric ultrasound of prostate: role in prostate cancer diagnosis

Recent advances in ultrasonography (US) technology established modalities, such as Doppler-US, HistoScanning, contrast-enhanced ultrasonography (CEUS), elastography, and micro-ultrasound. The early results of these US modalities have been promising, although there are limitations including the need for specialized equipment, inconsistent results, lack of standardizations, and external validation. In this review, we identified studies evaluating multiparametric ultrasonography (mpUS), the combination of multiple US modalities, for prostate cancer (PCa) diagnosis. In the past 5 years, a growing number of studies have shown that use of mpUS resulted in high PCa and clinically significant prostate cancer (CSPCa) detection performance using radical prostatectomy histology as the reference standard. Recent studies have demonstrated the role mpUS in improving detection of CSPCa and guidance for prostate biopsy and therapy. Furthermore, some aspects including lower costs, real-time imaging, applicability for some patients who have contraindication for magnetic resonance imaging (MRI) and availability in the office setting are clear advantages of mpUS. Interobserver agreement of mpUS was overall low; however, this limitation can be improved using standardized and objective evaluation systems such as the machine learning model. Whether mpUS outperforms MRI is unclear. Multicenter randomized controlled trials directly comparing mpUS and multiparametric MRI are warranted.

A systematic review and meta-analysis of Histoscanning™ in prostate cancer diagnostics

CONTEXT

The value of Histoscanning™ (HS) in prostate cancer (PCa) imaging is much debated, although it has been used in clinical practice for more than 10 years now.

OBJECTIVE

To summarize the data on HS from various PCa diagnostic perspectives to determine its potential.

MATERIALS AND METHODS

We performed a systematic search using 2 databases (Medline and Scopus) on the query "Histoscan*". The primary endpoint was HS accuracy. The secondary endpoints were: correlation of lesion volume by HS and histology, ability of HS to predict extracapsular extension or seminal vesicle invasion.

RESULTS

HS improved cancer detection rate "per core", OR = 16.37 (95% CI 13.2; 20.3), p < 0.0001, I² = 98% and "per patient", OR = 1.83 (95% CI 1.51; 2.21), p < 0.0001, I² = 95%. The pooled accuracy was markedly low: sensitivity - 0.2 (95% CI 0.19-0.21), specificity - 0.12 (0.11-0.13), AUC 0.12. 8 of 10 studiers showed no additional value for HS. The pooled accuracy with histology after RP was relatively better, yet still very low: sensitivity - 0.56 (95% CI 0.5-0.63), specificity - 0.23 (0.18-0.28), AUC 0.4. 9 of 12 studies did not show any benefit of HS.

CONCLUSION

This meta-analysis does not see the incremental value in comparing prostate Histoscanning with conventional TRUS in prostate cancer screening and targeted biopsy. HS proved to be slightly more accurate in predicting extracapsular extension on RP, but the available data does not allow us to draw any conclusions on its effectiveness in practice. Histoscanning is a modification of ultrasound for prostate cancer visualization. The available data suggest its low accuracy in screening and detecting of prostate cancer.

Artificial intelligence in multiparametric prostate cancer imaging with focus on deep-learning methods

Prostate cancer represents today the most typical example of a pathology whose diagnosis requires multiparametric imaging, a strategy where multiple imaging techniques are combined to reach an acceptable diagnostic performance. However, the reviewing, weighing and coupling of multiple images not only places additional burden on the radiologist, it also complicates the reviewing process. Prostate cancer imaging has therefore been an important target for the development of computer-aided diagnostic (CAD) tools. In this survey, we discuss the advances in CAD for prostate cancer over the last decades with special attention to the deep-learning techniques that have been designed in the last few years. Moreover, we elaborate and compare the methods employed to deliver the CAD output to the operator for further medical decision making.

Advanced ultrasound in the diagnosis of prostate cancer

The diagnosis of prostate cancer (PCa) can be challenging due to the limited performance of current diagnostic tests, including PSA, digital rectal examination and transrectal conventional US. Multiparametric MRI has improved PCa diagnosis and is recommended prior to biopsy; however, mp-MRI does miss a substantial number of PCa. Advanced US modalities include transrectal prostate elastography and contrast-enhanced US, as well as improved B-mode, micro-US and micro-Doppler techniques. These techniques can be combined to define a novel US approach, multiparametric US (mp-US). Mp-US improves PCa diagnosis but is not sufficiently accurate to obviate the utility of mp-MRI. Mp-US using advanced techniques and mp-MRI provide complementary information which will become even more important in the era of focal therapy, where precise identification of PCa location is needed.

"Real-time" Assessment of Surgical Margins During Radical Prostatectomy: State-of-the-Art

Histopathologic examination of the pathologic specimens using hematoxylin & eosin stains represents the backbone of the modern pathology. It is time-consuming; thus, "real-time" assessment of prostatic and periprostatic tissue has gained special interest in the diagnosis and management of prostate cancer. The current study focuses on the review of the different available techniques for "real-time" evaluation of surgical margins during radical prostatectomy (RP). We performed a comprehensive search of the Medline database to identify all the articles discussing "real-time" or intraoperative assessment of surgical margins during RP. Several filters were applied to the search to include only English articles performed on human subjects and published between January 2000 and March 2019. The search revealed several options for pathologic assessment of surgical margins including intraoperative frozen sections, confocal laser endomicroscopy, optical spectroscopy, photodynamic diagnosis, optical coherence tomography, multiphoton microscopy, structured illumination microscopy, 3D augmented reality, and ex vivo fluorescence confocal microscope. Frozen section represents the gold standard technique for real-time pathologic examinations of surgical margins during RP; however, several other options showed promising results in the initial clinical trials, and considering the rapid development in the field of molecular and cellular imaging, some of these options may serve as an alternative to frozen section.

Prostate Imaging Compared to Transperineal Ultrasound-guided biopsy for significant prostate cancer Risk Evaluation (PICTURE): a prospective cohort validating study assessing Prostate HistoScanning

BACKGROUND

Men with negative prostate biopsies or those diagnosed with low-risk or low-volume intermediate-risk prostate cancers often require a second prostate biopsy prior to a treatment decision. Prostate HistoScanning (PHS) is an ultrasound imaging test that might inform prostate biopsy in such men.

METHODS

PICTURE was a prospective, paired-cohort validating trial to assess the diagnostic accuracy of imaging in men requiring a further biopsy (clinicaltrials.gov, NCT01492270) (11 January 2012-29 January 2014). We enrolled 330 men who had undergone a prior TRUS biopsy but where diagnostic uncertainty remained. All eligible men underwent PHS and transperineal template prostate mapping (TTPM) biopsy (reference standard). Men were blinded to the imaging results until after undergoing TTPM biopsies. We primarily assessed the ability of PHS to rule out clinically significant prostate (negative predictive value [NPV] and sensitivity) for a target histological condition of Gleason ≥4+3 and/or a cancer core length (MCCL) ≥6 mm. We also assessed the role of visually estimated PHS-targeted biopsies.

RESULTS

Of the 330 men enrolled, 249 underwent both PHS and TTPM biopsy. Mean (SD) age was 62 (7) years, median (IQR) PSA 6.8 (4.98-9.50) ng/ml, median (IQR) number of previous biopsies 1 (1-2) and mean (SD) gland size 37 (15.5) ml. One hundred and forty six (59%) had no clinically significant cancer. PHS classified 174 (70%) as suspicious. Sensitivity was 70.3% (95% CI 59.8-79.5) and NPV 41.3% (95% CI 27.0-56.8). Specificity and positive predictive value (PPV) were 14.7% (95% CI 9.1-22.0) and 36.8% (95% CI 29.6-44.4), respectively. In all, 213/220 had PHS suspicious areas targeted with targeting sensitivity 13.6% (95% CI 7.3-22.6), specificity 97.6% (95% CI 93.1-99.5), NPV 61.6% (95% CI 54.5-68.4) and PPV 80.0% (95% CI 51.9-95.7).

CONCLUSIONS

PHS is not a useful test in men seeking risk stratification following initial prostate biopsy.

Anatomic and Molecular Imaging in Prostate Cancer

Prostate cancer is characterized by a complex set of heterogeneous disease states. This review aims to describe how imaging has been studied within each specific state. As physicians transition into an era of precision medicine, multiparametric magnetic resonance imaging (mpMRI) is proving to be a powerful tool leading the way for a paradigm shift in the diagnosis and management of localized prostate cancer. With further research and development, molecular imaging modalities will likely change the way we approach recurrent and metastatic disease. Given the range of possible oncological progression patterns, a thorough understanding of the underlying carcinogenesis, as it relates to imaging, is a requisite if we are to appropriately manage prostate cancer in future decades.

Evaluation of Prostate HistoScanning as a Method for Targeted Biopsy in Routine Practice

BACKGROUND

Prostate HistoScanning (PHS) is a tissue characterization system used to enhance prostate cancer (PCa) detection via transrectal ultrasound imaging.

OBJECTIVE

To assess the impact of supplementing systematic transrectal biopsy with up to three PHS true targeting (TT) guided biopsies on the PCa detection rate and preclinical patient assessment.

DESIGN, SETTING, AND PARTICIPANTS

This was a prospective study involving a cohort of 611 consecutive patients referred for transrectal prostate biopsy following suspicion of PCa. PHS-TT guided cores were obtained from up to three PHS lesions of ≥0.5cm³ per prostate and only one core per single PHS lesion. Histological outcomes from a systematic extended 12-core biopsy (Bx) scheme and additional PHS-TT guided cores were compared.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Comparison of PHS results and histopathology was performed per sextant. The χ² and Mann-Whitney test were used to assess differences. Statistical significance was set at p<0.05.

RESULTS AND LIMITATIONS

PHS showed lesions of ≥0.5cm³ in 312 out of the 611 patients recruited. In this group, Bx detected PCa in 59% (185/312) and PHS-TT in 87% (270/312; p<0.001). The detection rate was 25% (944/3744 cores) for Bx and 68% (387/573 cores) for PHS-TT (p<0.001). Preclinical assessment was significantly better when using PHS-TT: Bx found 18.6% (58/312) and 8.3% (26/312), while PHS-TT found 42.3% (132/312) and 20.8% (65/312) of Gleason 7 and 8 cases, respectively (p<0.001). PHS-TT attributed Gleason score 6 to fewer patients (23.4%, 73/312) than Bx did (32.4%, 101/312; p=0.0021).

CONCLUSIONS

Patients with a suspicion of PCa may benefit from addition of a few PHS-TT cores to the standard Bx workflow.

PATIENT SUMMARY

Targeted biopsies of the prostate are proving to be equivalent to or better than standard systematic random sampling in many studies. Our study results support supplementing the standard schematic transrectal ultrasound-guided biopsy with a few guided cores harvested using the ultrasound-based prostate HistoScanning true targeting approach in cases for which multiparametric magnetic resonance imaging is not available.

Does Prostate HistoScanning™ accurately identify prostate cancer, measure tumour volume and assess pathological stage prior to radical prostatectomy?

Objective

The objective of this paper is to assess the ability of Prostate HistoScanning™ (PHS) to accurately identify tumour volume, index lesion characteristics and pathological stage. PHS is a novel technology employing transrectal ultrasound scanning and software analysis of radiofrequency data to produce signatures for benign and cancerous tissues. Recent reports have suggested PHS is capable of characterising the index cancer lesion and disease multifocality and detecting extraprostatic extension (EPE).

Materials and methods

The index test was preoperative PHS on patients undergoing radical prostatectomy (RP). The reference test was the whole-mount pathological analysis of the RP specimen. PHS analysis estimated total tumour volumes, tumour volumes by prostate sextant, the locations and volumes of index lesions, and the presence and location of EPE.

Results

There was no correlation between PHS and histology total tumour volume estimates (Pearson coefficient –0.099), despite accounting for specimen fixation shrinkage (Pearson coefficient –0.070), nor among 144 prostate sextants in 24 patients (Pearson coefficient 0.14). Sensitivity and specificity of PHS in detecting foci > 0.2 ml were 63% and 53%, respectively; and 37% and 71%, respectively, for foci > 0.5 ml. Pearson correlation coefficient for index lesion volumes identified at pathology vs PHS was 0.065. PHS failed to locate accurately index lesion and pathological EPE.

Conclusions

PHS fails to identify total tumour volumes, tumour volumes prostate sextant, index lesion volumes and locations, and presence and location of EPE compared to RP pathology. PHS appears unsuitable for routine diagnostic clinical use in prostate cancer.

A Review of Imaging Methods for Prostate Cancer Detection

Imaging is playing an increasingly important role in the detection of prostate cancer (PCa). This review summarizes the key imaging modalities-multiparametric ultrasound (US), multiparametric magnetic resonance imaging (MRI), MRI-US fusion imaging, and positron emission tomography (PET) imaging-used in the diagnosis and localization of PCa. Emphasis is laid on the biological and functional characteristics of tumors that rationalize the use of a specific imaging technique. Changes to anatomical architecture of tissue can be detected by anatomical grayscale US and T2-weighted MRI. Tumors are known to progress through angiogenesis-a fact exploited by Doppler and contrast-enhanced US and dynamic contrast-enhanced MRI. The increased cellular density of tumors is targeted by elastography and diffusion-weighted MRI. PET imaging employs several different radionuclides to target the metabolic and cellular activities during tumor growth. Results from studies using these various imaging techniques are discussed and compared.

3D surface-based registration of ultrasound and histology in prostate cancer imaging

Several transrectal ultrasound (TRUS)-based techniques aiming at accurate localization of prostate cancer are emerging to improve diagnostics or to assist with focal therapy. However, precise validation prior to introduction into clinical practice is required. Histopathology after radical prostatectomy provides an excellent ground truth, but needs accurate registration with imaging. In this work, a 3D, surface-based, elastic registration method was developed to fuse TRUS images with histopathologic results. To maximize the applicability in clinical practice, no auxiliary sensors or dedicated hardware were used for the registration. The mean registration errors, measured in vitro and in vivo, were 1.5±0.2 and 2.1±0.5mm, respectively.

Sextant-Specific Analysis of Detection and Tumor Volume by HistoScanning™

INTRODUCTION

Published results of HistoScanning™ (HS) for prostate cancer (PCa) diagnostics are inconsistent and their value remains unclear. We prospectively analyzed the detection rate and tumor volume concordance in PCa patients.

MATERIAL AND METHODS

Two hundred and eighty-two patients with biopsy-proven PCa scheduled for radical prostatectomy (RP) were included. All patients underwent ultrasonographical examination by HS prior to surgery. HS was evaluated compared to RP specimen as to (1) the prediction of overall tumor volume and (2) accuracy of HS in detection of PCa lesions larger than 0.2/0.5 ml, separated for each sextant. For each sextant, receiver operating characteristic (ROC)-analysis and area under the curve were determined. Sensitivity and specificity were calculated and visualized in ROC-curves.

RESULTS

HS tends to underestimate volume of cancerous lesions, particularly larger lesions >8 ml. Using a 0.2 ml detection threshold, specificity and sensitivity of HS were between 29-68% and 46-78%. For a 0.5 ml detection threshold, sextant-specific specificity increased to 59-92% and sensitivity decreased to 16-54%. Stratification according to pre-operational PSA values did not improve performance characteristics of HS.

CONCLUSIONS

Our results do not support a significant contribution of HS to PCa diagnostics.

[Sonographic imaging of the prostate]

Accurate identification of the location of carcinoma in the prostate is essential for long-term therapeutic success, in particular for minimally invasive procedures. In recent years many new positive study results for prostate imaging have been reported which must be compared and evaluated and previous conservative assessments may need to be re-evaluated. In addition, combinations of different imaging techniques are increasingly being used in daily clinical routine. Due to technical advancements in sonographic imaging, such as elastography and contrast-enhanced ultrasound (CEUS), the detection rate of prostate cancer can be increased. An overview of the different imaging modalities and current literature are presented in this article.

A prospective comparative analysis of the accuracy of HistoScanning and multiparametric magnetic resonance imaging in the localization of prostate cancer among men undergoing radical prostatectomy

INTRODUCTION

There is increasing interest in using imaging in the detection and localization of prostate cancer (PCa). Both multiparametric magnetic resonance imaging (mpMRI) and HistoScanning (HS) have been independently evaluated in the detection and localization of PCa. We undertook a prospective, blinded comparison of mpMRI and HS for cancer localization among men undergoing radical prostatectomy.

METHODS

Following approval by the institutional review board, men scheduled to undergo radical prostatectomy, who had previously undergone mpMRI at our institution, were offered inclusion in the study. Those consenting underwent preoperative HS following induction of anesthesia; mpMRI, HS, and surgical step-section pathology were independently read by a single radiologist, urologist, and pathologist, respectively, in a blinded fashion. Disease maps created by each independent reader were compared and evaluated for concordance by a 5 persons committee consisting of 2 urologists, 2 pathologists, and 1 radiologist. Logistic regression for correlated data was used to assess and compare mpMRI and HS in terms of diagnostic accuracy for cancer detection. Generalized estimating equations based on binary logistic regression were used to model concordance between reader opinion and the reference standard assessment of the same lesion site or region as a function of imaging modality.

RESULTS

Data from 31/35 men enrolled in the trial were deemed to be evaluable. On evaluation of cancer localization, HS identified cancer in 36/78 (46.2%) regions of interest, as compared with 41/78 (52.6%) on mpMRI (P = 0.3968). The overall accuracy, positive predictive value, negative predictive value, and specificity for detection of disease within a region of interest were significantly better with mpMRI as compared with HS. HS detected 36/84 (42.9%) cancer foci as compared with 42/84 (50%) detected by mpMRI (P = 0.3678). Among tumors with Gleason score>6, mpMRI detected 19/22 (86.4%) whereas HS detected only 11/22 (50%, P = 0.0078). Similarly, among tumors>10mm in maximal diameter, mpMRI detected 28/34 (82.4%) whereas HS detected only 19/34 (55.9%, P = 0.0352).

CONCLUSION

In our institution, the diagnostic accuracy of HS was inferior to that of mpMRI in PCa for PCa detection and localization. Although our study warrants validation from larger cohorts, it would suggest that the HS protocol requires further refinement before clinical implementation.

Computer-aided transrectal ultrasound: does prostate HistoScanning™ improve detection performance of prostate cancer in repeat biopsies?

Background

An imaging tool providing reliable prostate cancer (PCa) detection and localization is necessary to improve common diagnostic pathway with ultrasound targeted biopsies. To determine the performance of transrectal ultrasound (TRUS) augmented by prostate HistoScanning^TM analysis (PHS) we investigated the detection of prostate cancer (PCa) foci in repeat prostate biopsies (Bx).

Methods

97 men with a mean age of 66.2 (44 – 82) years underwent PHS augmented TRUS analysis prior to a repeat Bx. Three PHS positive foci were defined in accordance with 6 bilateral prostatic sectors. Targeted Bx (tBx) limited to PHS positive foci and a systematic 14-core backup Bx (sBx) were taken. Results were correlated to biopsy outcome. Sensitivity, specificity, predictive accuracy, negative predictive value (NPV) and positive predictive value (PPV) were calculated.

Results

PCa was found in 31 of 97 (32 %) patients. Detection rate in tBx was significantly higher (p < .001). Detection rate in tBx and sBx did not differ on patient level(p ≥ 0.7). PHS sensitivity, specificity, predictive accuracy, PPV and NPV were 45 %, 83 %, 80 %, 19 % and 95 %, respectively.

Conclusions

PHS augmented TRUS identifies abnormal prostatic tissue. Although sensitivity and PPV for PCa are low, PHS information facilitates Bx targeting to vulnerable foci and results in a higher cancer detection rate. PHS targeted Bx should be considered in patients at persistent risk of PCa.

True targeting-derived prostate biopsy: HistoScanning™ remained inadequate despite advanced technical efforts

PURPOSE

To verify the reliability of HistoScanning™-based, true targeting (TT)-derived prostate biopsy.

METHODS

We relied on 40 patients suspicious for prostate cancer who underwent standard and TT-derived prostate biopsy. Sensitivity, specificity, positive predictive value, negative predictive value and the area under the curve (AUC) were assessed for the prediction of biopsy results per octant by HistoScanning™, using different HistoScanning™ signal volume cutoffs (>0, >0.2 and >0.5 ml).

RESULTS

Overall, 319 octants were analyzed. Of those, 64 (20.1 %) harbored prostate cancer. According to different HistoScanning™ signal volume cutoffs (>0, >0.2 and >0.5 ml), the AUCs for predicting biopsy results were: 0.51, 0.51 and 0.53, respectively. Similarly, the sensitivity, specificity, positive predictive and negative predictive values were: 20.7, 78.2, 17.4 and 81.6 %; 20.7, 82.0, 20.3 and 82.3 %; and 12.1, 94.6, 33.3 and 82.9 %, respectively.

CONCLUSIONS

Prediction of biopsy results based on HistoScanning™ signals and TT-derived biopsies was unreliable. Moreover, the AUC of TT-derived biopsies was low and did not improve when additional signal volume cutoffs were applied (>0.2 and >0.5 ml). We cannot recommend a variation of well-established biopsy standards or reduction in biopsy cores based on HistoScanning™ signals.

Transrectal Ultrasound (US), Contrast-enhanced US, Real-time Elastography, HistoScanning, Magnetic Resonance Imaging (MRI), and MRI-US Fusion Biopsy in the Diagnosis of Prostate Cancer

CONTEXT

Debates on overdiagnosis and overtreatment of prostate cancer (PCa) are ongoing and there is still huge uncertainty regarding misclassification of prostate biopsy results. Several imaging techniques that have emerged in recent years could overcome over- and underdiagnosis in PCa.

OBJECTIVE

To review the literature on transrectal ultrasound (TRUS)-based techniques (contrast enhancement, HistoScanning, elastography) and magnetic resonance imaging (MRI)-based techniques for a nonsystematic overview of their benefits and limitations.

EVIDENCE ACQUISITION

A comprehensive search of the PubMed database between August 2004 and August 2014 was performed. Studies assessing grayscale TRUS, contrast-enhanced (CE)-TRUS, elastography, HistoScanning, multiparametric MRI (mpMRI), and MRI-TRUS fusion biopsy were included. Publications before 2004 were included if they reported the principle or the first clinical results for these techniques.

EVIDENCE SYNTHESIS

Grayscale TRUS alone cannot detect PCa foci (detection rate 23-29%). TRUS-based (elastography) and MRI-based techniques (MRI-TRUS fusion biopsy) have significantly improved PCa diagnostics, with sensitivity of 53-74% and specificity of 72-95%. HistoScanning does not provide convincing or homogeneous results (specificity 19-82%). CE-TRUS seems to be user dependent; it is used in a low number of high-volume centers and has wide ranges for sensitivity (54-79%) and specificity (42-95%). For all the techniques reviewed, prospective multicenter studies with consistent definitions are lacking.

CONCLUSIONS

Standard grayscale TRUS is unreliable for PCa detection. Among the techniques reviewed, mpMRI and MRI-TRUS fusion biopsy seem to be suitable for enhancing PCa diagnostics. Elastography shows promising results according to the literature. CE-TRUS yields very inhomogeneous results and might not be the ideal technique for clinical practice. The value of HistoScanning must be questioned according to the literature.

PATIENT SUMMARY

New imaging modalities such as elastography and magnetic resonance imaging/transrectal ultrasound fusion biopsies have improved the detection of prostate cancer. This may lower the burden of overtreatment as a result of more precise diagnosis.

Quantitative ultrasound spectroscopic imaging for characterization of disease extent in prostate cancer patients

Three-dimensional quantitative ultrasound spectroscopic imaging of prostate was investigated clinically for the noninvasive detection and extent characterization of disease in cancer patients and compared to whole-mount, whole-gland histopathology of radical prostatectomy specimens. Fifteen patients with prostate cancer underwent a volumetric transrectal ultrasound scan before radical prostatectomy. Conventional-frequency (~5MHz) ultrasound images and radiofrequency data were collected from patients. Normalized power spectra were used as the basis of quantitative ultrasound spectroscopy. Specifically, color-coded parametric maps of 0-MHz intercept, midband fit, and spectral slope were computed and used to characterize prostate tissue in ultrasound images. Areas of cancer were identified in whole-mount histopathology specimens, and disease extent was correlated to that estimated from quantitative ultrasound parametric images. Midband fit and 0-MHz intercept parameters were found to be best associated with the presence of disease as located on histopathology whole-mount sections. Obtained results indicated a correlation between disease extent estimated noninvasively based on midband fit parametric images and that identified histopathologically on prostatectomy specimens, with an r(2) value of 0.71 (P<.0001). The 0-MHz intercept parameter demonstrated a lower level of correlation with histopathology. Spectral slope parametric maps offered no discrimination of disease. Multiple regression analysis produced a hybrid disease characterization model (r(2)=0.764, P<.05), implying that the midband fit biomarker had the greatest correlation with the histopathologic extent of disease. This work demonstrates that quantitative ultrasound spectroscopic imaging can be used for detecting prostate cancer and characterizing disease extent noninvasively, with corresponding gross three-dimensional histopathologic correlation.

Prostate histoscanning true targeting guided prostate biopsy: initial clinical experience

OBJECTIVE

To evaluate the feasibility of prostate histoscanning true targeting (PHS-TT) guided transrectal ultrasound (TRUS) biopsy.

METHODS

This is a prospective, single center, pilot study performed during February 2013-September 2013. All consecutive patients planned for prostate biopsy were included in the study, and all the procedure was performed by a single surgeon aided by the specialized true targeting software. Initially, the patients underwent PHS to map the abnormal areas within the prostate that were ≥0.2 cm(3). TRUS guided biopsies were performed targeting the abnormal areas with a specialized software. Additionally, routine bisextant biopsies were also taken. The final histopathology of the target cores was compared with the bisextant cores.

RESULTS

A total of 43 patients underwent combined 'targeted PHS guided' and 'standard 12 core systematic' biopsies. The mean volume of abnormal area detected by PHS is 4.3 cm(3). The overall cancer detection rate was 46.5 % (20/43) with systemic cores and target cores detecting cancer in 44 % (19/43) and 26 % (11/43), respectively. The mean % cancer/core length of the PHS-TT cores were significantly higher than the systematic cores (55.4 vs. 37.5 %. p < 0.05). In biopsy naïve patients, the cancer detection rate (43.7 % vs. 14.8 %. p = 0.06) and the cancer positivity of the cores (30.1 vs. 6.8 %. p < 0.01) of target cores were higher than those patients with prior biopsies.

CONCLUSION

PHS-TT is feasible and can be an effective tool for real-time guidance of prostate biopsies.

Histoscanning has low sensitivity and specificity for seminal vesicle invasion

OBJECTIVE

To examine the accuracy of HistoScanning (HS) in detecting seminal vesicle (SV) invasion (SVI) within prostate cancer (PCa) patients.

METHODS

We relied on our prospective institutional database. Patients who received HS before radical prostatectomy were included in the study cohort. An experienced HS examiner retrospectively reanalyzed the HS data blinded to patient characteristics and pathologic results. The HS results for every single SV were compared with the corresponding findings from the final pathologic report after radical prostatectomy. An area under the receiver operating characteristic curve for the prediction of SVI by HS was calculated. Depending on HS signal volume cut-offs (>0, >0.2, and >0.5 mL), the sensitivity, specificity, positive predictive value, and negative predictive value for the prediction of SVI were assessed.

RESULTS

Overall, 131 patients and 262 SVs were assessable. Of those, 23 (17.5%) men had SVI, and 39 (14.9%) single SVs were infiltrated by tumor overall. The area under the receiver operating characteristic curve for predicting SVI by HS was 0.54. Depending on the HS signal volume cut-offs (>0, >0.2, and >0.5 mL), the sensitivity, specificity, positive predictive value, and negative predictive value for predicting SVI were 76.9%, 10.8%, 13.1%, and 72.7%; 61.5%, 24.2%, 12.4%, and 78.3%; and 46.2%, 50.2%, 14.0%, and 84.2%, respectively.

CONCLUSION

HS results did not allow a reliable prediction of SVI within PCa patients. Despite, the application of HS signal volume cut-offs (>0.2 and >0.5 mL), the prediction of SVI within PCa patients remained insufficient.

A Workflow to Improve the Alignment of Prostate Imaging with Whole-mount Histopathology

RATIONALE AND OBJECTIVES

Evaluation of prostate imaging tests against whole-mount histology specimens requires accurate alignment between radiologic and histologic data sets. Misalignment results in false-positive and -negative zones as assessed by imaging. We describe a workflow for three-dimensional alignment of prostate imaging data against whole-mount prostatectomy reference specimens and assess its performance against a standard workflow.

MATERIALS AND METHODS

Ethical approval was granted. Patients underwent motorized transrectal ultrasound (Prostate Histoscanning) to generate a three-dimensional image of the prostate before radical prostatectomy. The test workflow incorporated steps for axial alignment between imaging and histology, size adjustments following formalin fixation, and use of custom-made parallel cutters and digital caliper instruments. The control workflow comprised freehand cutting and assumed homogeneous block thicknesses at the same relative angles between pathology and imaging sections.

RESULTS

Thirty radical prostatectomy specimens were histologically and radiologically processed, either by an alignment-optimized workflow (n = 20) or a control workflow (n = 10). The optimized workflow generated tissue blocks of heterogeneous thicknesses but with no significant drifting in the cutting plane. The control workflow resulted in significantly nonparallel blocks, accurately matching only one out of four histology blocks to their respective imaging data. The image-to-histology alignment accuracy was 20% greater in the optimized workflow (P < .0001), with higher sensitivity (85% vs. 69%) and specificity (94% vs. 73%) for margin prediction in a 5 × 5-mm grid analysis.

CONCLUSIONS

A significantly better alignment was observed in the optimized workflow. Evaluation of prostate imaging biomarkers using whole-mount histology references should include a test-to-reference spatial alignment workflow.

Does HistoScanning™ predict positive results in prostate biopsy? A retrospective analysis of 1,188 sextants of the prostate

PURPOSE

The role of HistoScanning™ (HS) in prostate biopsy is still indeterminate. Existing literature is sparse and controversial. To provide more evidence according to that important clinical topic, we analyzed institutional data from the Martini-Clinic, Prostate Cancer Center, Hamburg.

METHODS

Patients who received prostate biopsy and who also received HS were included in the study cohort. A single examiner, blinded to pathological results, re-analyzed all HS data in accordance with sextants of the prostate. Each sextant was considered as an individual case. Corresponding results from biopsy and HS were analyzed. The area under the receiver-operating characteristic curve (AUC) for the prediction of a positive biopsy by HS was calculated. Furthermore, sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) were assessed according to different HS signal volume cutoffs (>0, >0.2 and >0.5 ml).

RESULTS

Overall, 198 men were identified and 1,188 sextants were analyzed. The AUC to predict positive biopsy results by HS was 0.58. Sensitivity, specificity, PPV and NPV for HS to predict positive biopsy results per sextant, depending on different HS signal volume cutoffs (>0, >0.2 and >0.5 ml) were 84.1, 27.7, 29.5 and 82.9 %, 60.9, 50.6, 28.8 and 79.7 %, and 40.1, 73.3, 33.1 and 78.8 %, respectively.

CONCLUSIONS

Positive HS signals do not accurately predict positive prostate biopsy results according to sextant analysis. We cannot recommend a variation of well-established random biopsy patterns or reduction of biopsy cores in accordance with HS signals at the moment.

Does prostate HistoScanning™ play a role in detecting prostate cancer in routine clinical practice? Results from three independent studies

OBJECTIVES

To evaluate the ability of prostate HistoScanning™ (PHS; Advanced Medical Diagnostics, Waterloo, Belgium) to detect, characterize and locally stage prostate cancer, by comparing it with transrectal ultrasonography (TRUS)-guided prostate biopsies, transperineal template prostate biopsies (TTBs) and whole-mount radical prostatectomy specimens.

SUBJECTS AND METHODS

Study 1. We recruited 24 patients awaiting standard 12-core TRUS-guided biopsies of the prostate to undergo PHS immediately beforehand. We compared PHS with the TRUS-guided biopsy results in terms of their ability to detect cancer within the whole prostate and to localize it to the correct side and to the correct region of the prostate. Lesions that were suspicious on PHS were biopsied separately. Study 2. We recruited 57 patients awaiting TTB to have PHS beforehand. We compared PHS with the TTB pathology results in terms of their ability to detect prostate cancer within the whole gland and to localize it to the correct side and to the correct sextant of the prostate. Study 3. We recruited 24 patients awaiting radical prostatectomy for localized prostate cancer to undergo preoperative PHS. We compared PHS with standardized pathological analysis of the whole-mount prostatectomy specimens in terms of their measurement of total tumour volume within the prostate, tumour volume within prostate sextants and volume of index lesions identified by PHS.

RESULTS

The PHS-targeted biopsies had an overall cancer detection rate of 38.1%, compared with 62.5% with standard TRUS-guided biopsies. The sensitivity and specificity of PHS for localizing tumour to the correct prostate sextant, compared with standard TRUS-guided biopsies, were 100 and 5.9%, respectively. The PHS-targeted biopsies had an overall cancer detection rate of 13.4% compared with 54.4% for standard TTB. PHS had a sensitivity and specificity for cancer detection in the posterior gland of 100 and 13%, respectively, and for the anterior gland, 6 and 82%, respectively. We found no correlation between total tumour volume estimates from PHS and radical prostatectomy pathology (Pearson correlation coefficient -0.096). Sensitivity and specificity of PHS for detecting tumour foci ≥0.2 mL in volume were 63 and 53%.

CONCLUSIONS

These three independent studies in 105 patients suggest that PHS does not reliably identify and characterize prostate cancer in the routine clinical setting.

Prostate cancer detection and diagnosis: the role of MR and its comparison with other diagnostic modalities--a radiologist's perspective

It is now universally recognized that many prostate cancers are over-diagnosed and over-treated. The European Randomized Study of Screening for Prostate Cancer from 2009 evidenced that, to save one man from death from prostate cancer, over 1400 men need to be screened, and 48 need to undergo treatment. The detection of prostate cancer is traditionally based on digital rectal examination (DRE) and the measurement of serum prostate-specific antigen (PSA), followed by ultrasound-guided biopsy. The primary role of imaging for the detection and diagnosis of prostate cancer has been transrectal ultrasound (TRUS) guidance during biopsy. Traditionally, MRI has been used primarily for the staging of disease in men with biopsy-proven cancer. It has a well-established role in the detection of T3 disease, planning of radiation therapy, especially three-dimensional conformal or intensity-modulated external beam radiation therapy, and planning and guiding of interstitial seed implant or brachytherapy. New advances have now established that prostate MRI can accurately characterize focal lesions within the gland, an ability that has led to new opportunities for improved cancer detection and guidance for biopsy. Two new approaches to prostate biopsy are under investigation. Both use pre-biopsy MRI to define potential targets for sampling, and the biopsy is performed either with direct real-time MR guidance (in-bore) or MR fusion/registration with TRUS images (out-of-bore). In-bore and out-of-bore MRI-guided prostate biopsies have the advantage of using the MR target definition for the accurate localization and sampling of targets or suspicious lesions. The out-of-bore method uses combined MRI/TRUS with fusion software that provides target localization and increases the sampling accuracy of TRUS-guided biopsies by integrating prostate MRI information with TRUS. Newer parameters for each imaging modality, such as sonoelastography or shear wave elastography, contrast-enhanced ultrasound and MRI elastography, show promise to further enrich datasets.

Imaging and Markers as Novel Diagnostic Tools in Detecting Insignificant Prostate Cancer: A Critical Overview

Recent therapeutic advances for managing low-risk prostate cancer include the active surveillance and focal treatment. However, locating a tumor and detecting its volume by adequate sampling is still problematic. Development of predictive biomarkers guiding individual therapeutic choices remains an ongoing challenge. At the same time, prostate cancer magnetic resonance imaging is gaining increasing importance for prostate diagnostics. The high morphological resolution of T2-weighted imaging and functional MRI methods may increase the specificity and sensitivity of diagnostics. Also, recent studies founded an ability of novel biomarkers to identify clinically insignificant prostate cancer, risk of progression, and association with poor differentiation and, therefore, with clinical significance. Probably, the above mentioned methods would improve tumor characterization in terms of its volume, aggressiveness, and focality. In this review, we attempted to evaluate the applications of novel imaging techniques and biomarkers in assessing the significance of the prostate cancer.

The PICTURE study -- prostate imaging (multi-parametric MRI and Prostate HistoScanning™) compared to transperineal ultrasound guided biopsy for significant prostate cancer risk evaluation

OBJECTIVE

The primary objective of the PICTURE study is to assess the negative predictive value of multi-parametric MRI (mp-MRI) and Prostate HistoScanning™ (PHS) in ruling-out clinically significant prostate cancer.

PATIENTS AND METHODS

PICTURE is a prospective diagnostic validating cohort study conforming to level 1 evidence. PICTURE will assess the diagnostic performance of multi-parametric Magnetic Resonance Imaging (mp-MRI) and Prostate HistoScanning™ (PHS) ultrasound. PICTURE will involve validating both index tests against a reference test, transperineal Template Prostate Mapping (TPM) biopsies, which can be applied in all men under evaluation. Men will be blinded to the index test results and both index tests will be reported prospectively prior to the biopsies being taken to ensure reporter blinding. Paired analysis of each of the index tests to the reference test will be done at patient level. Those men with an imaging lesion will undergo targeted biopsies to assess the clinical utility of sampling only suspicious areas. The study is powered to assess the negative predictive value of these imaging modalities in ruling-out clinically significant prostate cancer.

DISCUSSION

The PICTURE study aims to assess the performance characteristics of two imaging modalities (mp-MRI and Prostate HistoScanning) for their utility in the prostate cancer pathway. PICTURE aims to identify if either imaging test may be useful for ruling out clinically significant disease in men under investigation, and also to examine if either imaging modality is useful for the detection of disease. Recruitment is underway and expected to complete in 2014.

[Imaging of the prostate]

Recently several new technologies for prostate imaging have been developed. The aim of these technologies was to improve the diagnosis of prostate cancer. Especially the transrectal ultrasound (TRUS) has been refined to the so-called enhanced ultrasound, as regular grey scale TRUS has limited ability to identify cancer lesions in the prostate. In several studies elastography has shown good capability to identify cancer lesions in the prostate as well as to absolutely increase the detection rate of randomized biopsies by up to 10 %.. Contrast-enhanced ultrasound shows varying results in the published literature with increased detection rates on the one hand and unchanged detection rates relative to randomized biopsy on the other hand. The online available ANNA/C-TRUS system shows detection rates with six targeted biopsies that are comparable to the published detection rates of randomized saturation biopsies. Direct systematic comparison to randomized biopsies is missing. The Histoscanning system currently provides the poorest data as no biopsy studies are available. Multicenter trials are mandatory for all new imaging technologies in order to implement them as standard into clinical practice.

Focal low-dose rate brachytherapy for the treatment of prostate cancer

Whole-gland low-dose rate (LDR) brachytherapy has been a well-established modality of treating low-risk prostate cancer. Treatment in a focal manner has the advantages of reduced toxicity to surrounding organs. Focal treatment using LDR brachytherapy has been relatively unexplored, but it may offer advantages over other modalities that have established experiences with a focal approach. This is particularly true as prostate cancer is being detected at an earlier and more localized stage with the advent of better detection methods and newer imaging modalities.

Utility of Histoscanning™ prior to prostate biopsy for the diagnosis of prostate adenocarcinoma

OBJECTIVES

HistoScanning™ (HS) is a method of ecographic diagnosis of prostate cancer. We analyze the effectiveness of the HS realization prior to the biopsies for the prostate adenocarcinoma diagnosis.

MATERIAL AND METHODS

From August to October 2012 we have carried out a study with HS prior to the biopsies in 32 patients. In all cases sextants transrectal biopsies have been realized (two cores in each sextant) in the periphery zone. In those sextants in which there were suspicious areas with HS, the biopsies were addressed to those areas. Transperineal biopsies were added to those zones placed in the half-front or apical prostatic zone. The medium age was 63.7 years (range 40-82) with a medium PSA of 8.0 ng/ml (range 3.5-36.2) and a medium prostatic volume of 46.6cc (range 18.2-103.2). In eight cases it was the first biopsy, in 14 cases they were repetition biopsies and 10 patients had a previous diagnosis of prostate adenocarcinoma (8 in a program of active surveillance and 2 T1a in RTU of previous prostate).

RESULTS

In the 32 patients a medium of 7,5 zones were biopsied (range 6-9) with a total of 239 zones studied. There were identified a medium of 3.2 zones with suspicious areas (ZS) with HS (range 2-5) with a total of 103 ZS. In 72 zones of 25 patients it was found adenocarcinoma or PIN (2 PIN, 11 score Gleason 6, 7 score Gleason 7, 3 score Gleason 8 and 2 score Gleason 9). There were 35 positive false zones in 20 patients (11 normal parenquima and 9 chronic inflammation). Negative falses were produced in 5 zones in 5 patients (2PIN, 2 score Gleason 6 and 1 score Gleason 7) although in all 5 cases adenocarcinoma was encountered (o discovered) in other zones. The HS presented a sensibility of a 93.5% with a specificity of 79.5%. The positive predictive value was of the 67.35% with a negative predictive value of 96.5%.

CONCLUSIONS

In spite of being a selected serie, with a high rate of patients with adenocarcinoma, the exploration with HS has presented a great sensibility and a high negative predictive value. These data, although they must be confirmed in less selected series, state that the prior exploration with HS can help as in the diagnostic in the biopsies as in the follow-up of programs of active surveillance.

Ultrasonography in prostate cancer: current roles and potential applications in radiorecurrent disease

The use of ultrasound technology for prostate cancer imaging has evolved over many years. In order to fully appreciate today's application of prostate ultrasound in the primary diagnostic setting as well as for radiorecurrent prostate cancer, it is helpful to understand the progression of this technology from its inception. This review begins with a brief history of the development of ultrasonography for the prostate. This is followed by a summary of the data evaluating ultrasound in the primary diagnosis of prostate cancer. Its application in the post-treatment setting is then addressed. Finally, several emerging technologies are discussed, including contrast-enhanced ultrasound, elastography and HistoScanning. These new modalities may hold promise for identifying incompletely ablated prostate tissue following radiation therapy or other ablative techniques.

Computer-aided (HistoScanning) biopsies versus conventional transrectal ultrasound-guided prostate biopsies: do targeted biopsy schemes improve the cancer detection rate?

OBJECTIVE

To define potential improvement in prostate cancer detection by application of a computer-aided, targeted, biopsy regimen using HistoScanning.

MATERIALS AND METHODS

We analyzed 80 patients who underwent systematic transrectal, targeted transrectal, and targeted perineal biopsies. Each patient was diagnosed preoperatively by HistoScanning, defining a maximum of 3 suspicious areas. These areas were biopsied, both transrectally and via the perineum, with a maximum of 3 cores per location.

RESULTS

We detected prostatitis in 30 patients (37.5%), premalignant lesions in 10 (12.5%), and prostate cancer in 28 (35%). The transrectal technique was used to detect 78.6% of all cancers using 14 cores by systematic biopsy. With a maximum of 9 targeted cores, 82.1% of all cancers were detected with the targeted perineal approach and 53.6% were detected with the targeted transrectal approach. Although our data did not show significant difference in the performance of targeted transperineal compared with systematic transrectal biopsies, the detection rate of targeted transrectal biopsies was significantly lower.

CONCLUSION

The presented targeted biopsy scheme achieved an overall detection rate of 85% of prostate-specific antigen-relevant pathologic lesions within the prostate. Thus, the presented procedure shows an improved detection rate compared with standard systematic prostate biopsies, and the number of cores required is reduced. Furthermore, the perineal HistoScanning-aided approach seems to be superior to the transrectal approach with respect to the prostate cancer detection rate. The presented procedure might be a step toward reliable ultrasound-based tissue characterization and toward fulfilling the requirements of novel therapeutic strategies.

Prostate HistoScanning: a screening tool for prostate cancer?

OBJECTIVE

To evaluate Prostate HistoScanning as a screening tool for prostate cancer in a pilot study.

METHODS

During a 6-month period, 94 men with normal or suspicious digital rectal examination, normal or elevated prostate-specific antigen, or an increased prostate-specific antigen velocity were examined with Prostate HistoScanning. Based on these parameters and HistoScanning analysis, 41 men were referred for prostate biopsy under computer-aided ultrasonographic guidance. The number of random biopsy cores varied depending on the prostate volume. Targeted biopsies were taken in the case of computer-aided ultrasonographic area suspicious for malignancy. A logistic regression analysis was carried out to estimate the probability of resulting in a positive prostate biopsy based on the HistoScanning findings.

RESULTS

Following a logistic regression analysis, after adjusting for age, digital rectal examination, serum prostate-specific antigen level, prostate volume and tumor lesion volume, every cancer volume increase of 1 mL estimated by HistoScanning was associated with a nearly threefold increase in the probability of resulting in a positive biopsy (odds ratio 2.9; 95% confidence interval 1.2-7.0; P-value 0.02). Prostate cancer was found in 17 of 41 men (41%). In patients with cancer, computer-aided ultrasonography-guided biopsy was 4.5-fold more likely to detect cancer than random biopsy. The prostate cancer detection rate for random biopsy and directed biopsy was 13% and 58%, respectively. HistoScanning-guided biopsy significantly decreased the number of biopsies necessary (P-value <0.0001).

CONCLUSIONS

Our findings suggest that Prostate HistoScanning might be helpful for the selection of patients in whom prostate biopsies are necessary. This imaging technique can be used to direct biopsies in specific regions of the prostate with a higher cancer detection rate.

[Multiparametric MRI, elastography, contrastenhanced TRUS. Are there indications with reliable diagnostic advantages before prostate biopsy?]

Prostate cancer (PCA) is the most common malignancy in men with an increasing incidence and is responsible for about 11,000 deaths per year in Germany. Fortunately, the mortality of PCA has decreased in recent years despite the rising incidence reflecting improvements in diagnostic methods. Many new innovations in imaging techniques for PCA are available and may be helpful in early detection of PCA. Contrast-enhanced sonography, computer-assisted sonography, elastography and multiparametric magnetic resonance imaging (MRI) seem to be the most promising methods to increase the detection rate of PCA during diagnostic work-up. The value of these new innovative techniques concerning improvement in PCA detection is reviewed.

Current status of transrectal ultrasound techniques in prostate cancer

PURPOSE OF REVIEW

Present the current status of transrectal ultrasound imaging in prostate cancer (PCa) and discuss the latest techniques now under preclinical evaluation.

RECENT FINDINGS

Three-dimensional ultrasound and quantification techniques are superior to two-dimensional ultrasound in visualizing PCa and can be beneficial in staging prior to operation. Doppler-guided biopsies are more likely to yield positive results, especially when high Gleason scores are present. Furthermore, Vardenafil usage strengthens Doppler enhancement and can help in increasing the diagnostic accuracy of Doppler. Multiple studies show elastography to be a promising new addition to the ultrasound investigations for detection of PCa. Especially the recently introduced Shear Wave Elastography shows decreased user dependency and increased PCa detection rates. MRI can also aid in the diagnostics of PCa. However, MRI-guided biopsies are more complicated compared to ultrasound guidance. MRI/ultrasound fusion combines best of both techniques and, although just recently emerged, the studies available show promising PCa detection rates.

SUMMARY

Technical improvements in classical ultrasound modalities (2D/3D-greyscale, Doppler) and new modalities (elastography/MRI/ultrasound fusion) raised the accuracy of PCa detection. Especially latest elastography and MRI/ultrasound fusion are showing promising results in PCa visualization.

Intraprostatic targeting

PURPOSE OF REVIEW

The ability to accurately localize and target prostate cancer, whether for staging or future interventions, is an important concept in prostate cancer management. In this review, we describe the emerging technologies that allow for enhanced visualization and precise targeting of the prostate cancer.

RECENT FINDINGS

Uses of prostate-specific antigen and conventional prostate biopsy with image-blinded random systematic techniques have led to overdiagnosis of insignificant cancer and underdiagnosis of significant cancer. Active surveillance and focal therapy have become hot topics in prostate cancer management as the incidence of low-risk prostate cancer rises. For either management, it is essential to localize, characterize, and target the clinically important cancer in the prostate. Emerging techniques in ultrasound as well as MRI modalities allow for enhancement of tumor visualization, and characterization. Digital mapping technique of biopsy trajectory is an emerging technique that allows for three-dimensional mapping of biopsy-proven cancer lesions as well as potential future delivery of focal therapy. Molecular or cancer-specific targeting is promising for specific imaging and therapeutic approach at the cell level.

SUMMARY

Emerging technologies improve clinically relevant prostate cancer identification using digitalized multiparametric anatomical and functional imaging and enhance the ability to precisely target the known-cancer.

Comprehensive report on prostate cancer misclassification by 16 currently used low-risk and active surveillance criteria

What's known on the subject? and What does the study add? Prostate cancer characterisation, based on laboratory findings, clinical examination and histopathological cancer features that are used to define selection criteria for AS, is not ideal. Consequently, a panel of strict or more lenient criteria to select patients for AS have been published. Studies investigating the relationship between pretreatment variables and final pathology have been done in the past showing the risk of cancer misclassification for some criteria. No study has presented an overview of cancer selection using a panel of 16 currently used AS criteria that is presented in the present study. In an exactly defined cohort after radical prostatectomy, each set of criteria was used as a diagnostic test to separate between patients with more favourable (pT2, no Gleason upgrade between biopsy grading and final pathology) and unfavourable cancer features (pT3, pN+, Gleason upgrade). To the best of our knowledge a comparison of test quality criteria for AS criteria given by sensitivity, specificity, positive and negative predictive value and likelihood ratio has not yet been reported. Moreover, we showed that tumour characterisation, by a formally sufficient 12-core biopsy, in the present dataset harboured a risk of ≈20% that unfavourable cancer features were missed regardless of whether strict or more lenient selection criteria for AS were chosen.

OBJECTIVE

To evaluate final histopathological features among men diagnosed with prostate cancer eligible for low-risk (LR) or active surveillance (AS) criteria.

PATIENTS AND METHODS

Retrospective application of 16 definitions for AS or LR prostate cancer to a contemporary (January 2008 to March 2011) open retropubic radical prostatectomy (RRP) series of 1745 patients.

EXCLUSION CRITERIA

neoadjuvant hormones, radiotherapy, inadequate histopathological reports, <10 biopsy cores. Report on the number of men with insignificant tumours (defined as: ≤pT2, Gleason score ≤6, tumour volume <0.5 mL) and men who had unfavourable tumour characteristics on final pathology (defined as: extracapsular extension or seminal vesicle invasion or lymph node metastasis or Gleason upgrading). Sensitivity, specificity, positive predictive value (PPV) and negative predictive values (NPV) were calculated.

RESULTS

Eligibility of patients in the final study cohort (n = 1070) varied from 5.1% to 92.7% depending on the AS or LR criteria used. Final pathology revealed 77 insignificant cancers and 578 patients who had unfavourable histopathological criteria. The detection rate for insignificant cancers on final pathology was variable ranging from 7.8% to 28.3% depending on the AS- or LR-prediction tool used; unfavourable tumour characteristics were found in up to 33.5% on final pathology. The sensitivity, specificity, PPV and NPV were 8.5-97.9%, 24.7-97.8%, 67.7-89.1% and 45.3-78.2%, respectively. The likelihood ratio to correctly identify a patient with LR disease on final pathology ranged from 1.3 to 8.

CONCLUSIONS

AS or LR criteria have a significant risk of cancer misclassification. Better prediction tools are needed to improve these criteria. Re-biopsy might improve safety and should be considered more frequently in patients who opt for AS.