Innovations in diagnostic imaging of localized prostate cancer

Comparative Assessment of Different Ultrasound Technologies in the Detection of Prostate Cancer: A Systematic Review and Meta-Analysis

The present study aimed to assess the diagnostic test accuracy of different ultrasound scanning technologies in the detection of prostate cancer. A systematic search was conducted using the Cochrane Guidelines for Screening and Diagnostic Tests. We performed a systematic search in the international databases PubMed, Medline, Ovid, Embase and Cochrane Library. Searches were designed to find all studies that evaluated Micro-US, mpUS, SWE and CEUS as the main detection modalities for prostate cancer. This study was registered with Research Registry of systematic review and meta-analysis. The QUADAS-2 tool was utilized to perform quality assessment and bias analysis. The literature search generated 1376 studies. Of these, 320 studies were screened for eligibility, with 1056 studies being excluded. Overall, 26 studies with a total of 6370 patients met the inclusion criteria. The pooled sensitivity for grayscale, CEUS, SWE, Micro-US and mpUS modalities were 0.66 (95% CI 0.54-0.73) 0.73 (95% CI 0.58-0.88), 0.82 (95% CI 0.75-0.90), 0.85 (95% CI 0.76-0.94) and 0.87 (95% CI 0.71-1.03), respectively. Moreover, the pooled specificity for grayscale, CEUS, SWE, Micro-US and mpUS modalities were 0.56 (95% CI 0.21-0.90), 0.78 (95% CI 0.67-0.88), 0.76 (95% CI 0.65-0.88), 0.43 (95% CI 0.28-0.59) and 0.68 (95% CI 0.54-0.81), respectively. In terms of sensitivity, substantial heterogeneity between studies was detected (I2 = 72%, p = 0.000 < 0.05). In relation to specificity, extreme heterogeneity was detected (I2 = 93%, p = 0.000 < 0.05). Some studies proved that advanced ultrasound modalities such as mpUS, Micro-US, shear-wave elastography, contrast enhanced and micro-ultrasound are promising methods for the detection of prostate cancer.

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.

Internal Fusion: exact correlation of transrectal ultrasound images of the prostate by detailed landmarks over time for targeted biopsies or follow-up

PURPOSE

Innovative imaging modalities are applied for diagnosing and follow-up of prostate cancer (PCa). To perform authentic targeted biopsies and evaluate prostate changes, it is essential to reliably identify and hit targets in their true anatomical location over time. A newly described image correlation method (Internal Fusion) allows precise correlation of serial transrectal ultrasound (TRUS) images in vitro and vivo. Identifiable morphologic structures such as prostatic calcifications define internal anchor points (Internal Landmarks) to facilitate exact correlation.

METHODS

After verification of Internal Fusion in vitro, 83 patients were included from January to August 2017 with at least one prior series of 5-mm spaced TRUS images stored as computed tomographic (US-CT) online data set. Two experienced operators collected new images in correlation with each cross-section of the previous examinations based on Internal Landmarks.

RESULTS

Of the 83 patients, fifty (60%) had prior negative biopsies. Fourteen (17%) wished US-CT targeted biopsies and PCa were detected in 7/14 patients (50%). Overall, accurate imaging correlations were attained in 369/397 slices (93%). In initial and repeat biopsy, 31/31 and 35/35 images could be correlated detecting PCa in 5/8 (63%) and 2/6 patients (33%). The longest observation of prostate changes over time (Trend Monitoring) with accurate image correlation was 8 years and 6 months.

CONCLUSIONS

Internal Fusion by Internal Landmarks ensures exact correlation in long-term follow-up. It is possible to precisely monitor trends in prostate tissue changes. In case of PCa suspicion, biopsies could be targeted with high accuracy by Internal Fusion, even over time.

Complications and prostate cancer diagnosis rate of TRUS prostate biopsies using 16 and 18G needles by Clavien scoring

AIM

We aimed to compare the 18 and 16-Gauge (G) needles used in transrectal ultrasonography (TRUS)-guided needle biopsy for cancer detection rates and complications using the Clavien Scoring System.

MATERIALS AND METHODS

The 80 patients who were included in the study were randomized and divided into two groups. Group 1 (n = 36) had a TRUS-guided prostate biopsy with an 18G needle and Group 2 had a 16G needle (n = 44). The hematuria, bleeding assessment, and infection events were evaluated on a daily basis. These complications were graded according to the Clavien Scoring.

RESULTS

In Group 1, only five (13%) patients were diagnosed with prostate cancer, and three patients were reported to have atypical small acinar proliferation (ASAP). In Group 2, 16 (36%) patients were diagnosed with prostate cancer and one patient was reported to have ASAP. The difference in the prostate cancer detection rate between the groups was statistically significant. According to the Clavien grading system, the complications were at the Grade 1 level in 25 people in Group 1 in 29 people in Group 2. Grade 2 level complications were not observed in either group. While one person was Grade 3 in Group 1, two people in Group 2 had this rate. There were no significant differences between the groups.

CONCLUSIONS

We found that cancer detection rate increased by increasing the thickness of the needle used in TRUS-guided prostate biopsy without any increase in the complications.

Evidence-based guideline recommendations on multiparametric magnetic resonance imaging in the diagnosis of prostate cancer: A Cancer Care Ontario clinical practice guideline

This clinical guideline focuses on: 1) the use of multiparametric magnetic resonance imaging (mpMRI) in diagnosing clinically significant prostate cancer (CSPC) in patients with an elevated risk of CSPC and who are biopsy-naïve; and 2) the use of mpMRI in diagnosing CSPC in patients with a persistently elevated risk of having CSPC and who have a negative transrectal ultrasound (TRUS)-guided systematic biopsy. The methods of the Practice Guideline Development Cycle were used. MEDLINE, EMBASE, the Cochrane Library (1997‒April 2014), main guideline websites, and relevant annual meeting abstracts (2011‒2014) were searched. Internal and external reviews were conducted. The two main recommendations are: Recommendation 1: In patients with an elevated risk of CSPC (according to prostate-specific antigen [PSA] levels and/or nomograms) who are biopsy-naïve: mpMRI followed by targeted biopsy (biopsy directed at cancer-suspicious foci detected with mpMRI) should not be considered the standard of care.Data from future research studies are essential and should receive high-impact trial funding to determine the value of mpMRI in this clinical context.Recommendation 2: In patients who had a prior negative TRUS-guided systematic biopsy and demonstrate an increasing risk of having CSPC since prior biopsy (e.g., continued rise in PSA and/or change in findings from digital rectal examination): mpMRI followed by targeted biopsy may be considered to help in detecting more CSPC patients compared with repeated TRUS-guided systematic biopsy.

Performance of PI-RADS version 1 versus version 2 regarding the relation with histopathological results

PURPOSE

Aim of this study was to compare the diagnostic performance of PI-RADS version 1 (v1) and version 2 (v2) in the detection of prostate cancer (PCa).

METHODS

Multiparametric MRIs (mpMRI) of 50 consecutive patients with biopsy proven PCa, which had originally been evaluated according to PIRADS v1, were now retrospectively re-evaluated, comparing PI-RADS v1 and v2. MpMRI data were evaluated in comparison with histopathological whole-mount step-section slides. MRI examinations included T2-weighted, diffusion-weighted, and dynamic contrast-enhanced MRI.

RESULTS

Overall PI-RADS v1 showed a significantly larger discriminative ability of tumor detection: PI-RADS v1 AUC 0.96 (95 % CI 0.94-0.98) and v2 AUC 0.90 (95 % CI 0.86-0.94). For peripheral zone lesions, PI-RADS v1 showed a significantly larger ability of PCa discrimination: v1 AUC 0.97 (95 % CI 0.95-0.99) and v2 AUC 0.92 (95 % CI 0.88-0.96). For transition zone lesions, PI-RADS v1 showed more discrimination: v1 AUC 0.96 (95 % CI 0.92-1.00) and v2 0.90 (95 % CI 0.83-0.97), but the difference was not significant. PI-RADS v2 resulted in significantly more false negative results (3 % in v1, 14 % in v2) and a comparable number of true positive results (82 % in v1, 80 % in v2).

CONCLUSION

PI-RADS v2 uses a simplified approach, but shows a lower diagnostic accuracy. This could lead to a higher rate of false negative results with the risk of missing tumors within low PI-RADS score levels. Therefore, its use cannot be recommended unconditionally, and further improvement should be considered.

Multiparametric Magnetic Resonance Imaging in the Diagnosis of Prostate Cancer: A Systematic Review

A systematic review was conducted to investigate the use of multiparametric magnetic resonance imaging (MPMRI) followed by targeted biopsy in the diagnosis of clinically significant prostate cancer (CSPC) and to compare it with transrectal ultrasound-guided (TRUS-guided) systematic biopsy in patients with an elevated risk of prostate cancer who are either biopsy-naive or who have a previous negative TRUS-guided biopsy. MEDLINE, PubMed and EMBASE (1997 to April 2014), the Cochrane Library and six relevant conferences were searched to find eligible studies. Search terms indicative of 'prostate cancer' and 'magnetic resonance imaging' with their alternatives were used. Twelve systematic reviews, 52 full texts and 28 abstracts met the preplanned study selection criteria; data from 15 articles were extracted. In patients with an elevated risk of prostate cancer who were biopsy-naive, MPMRI followed by targeted biopsy could detect 2-13% of CSPC patients whom TRUS-guided systematic biopsy missed; TRUS-guided systematic biopsy could detect 0-7% of CSPC patients whom MPMRI followed by targeted biopsy missed. In patients with an elevated risk of prostate cancer who had a previous negative TRUS-guided biopsy, MPMRI followed by targeted biopsy detected more CSPC patients than repeated TRUS-guided systematic biopsy in all four studies, with a total of 516 patients, but only one study reached a statistically significant difference. In patients with an elevated risk of prostate cancer who are biopsy-naive, there is insufficient evidence for MPMRI followed by targeted biopsy to be considered the standard of care. In patients who had a prior negative TRUS-guided systematic biopsy and show a growing risk of having CSPC, MPMRI followed by targeted biopsy may be helpful to detect more CSPC cases as opposed to a repeat TRUS-guided systematic biopsy.

[Prostate biopsy: Procedure in the clinical routine]

Over the last decade there has been a 25% decrease in the mortality rates for prostate cancer. The reasons for this significant decrease are most likely associated with the application of urological screening tests. The main tools for early detection are currently increased public awareness of the disease, prostate-specific antigen (PSA) tests and transrectal ultrasound (TRUS) guided topographically assignable biopsy sampling. Together with the histopathological results these features provide essential information for risk stratification, diagnostics and therapy decisions. The evolution of prostate biopsy techniques as well as the use of PSA testing has led to an increased identification of asymptomatic men, where further clarification is necessary. Significant efforts and increased clinical research focus on determining the appropriate indications for a prostate biopsy and the optimal technique to achieve better detection rates. The most widely used imaging modality for the prostate is TRUS; however, there are no clearly defined standards for the clinical approach for each individual biopsy procedure, dealing with continuous technical optimization and in particular the developments in imaging. In this review the current principles, techniques, new approaches and instrumentation of prostate biopsy imaging control are presented within the framework of the structured educational approach.

Multiparametric ultrasound in the detection of prostate cancer: a systematic review

PURPOSE

To investigate the advances and clinical results of the different ultrasound modalities and the progress in combining them into multiparametric UltraSound (mpUS).

METHODS

A systematic literature search on mpUS and the different ultrasound modalities included: greyscale ultrasound, computerized transrectal ultrasound, Doppler and power Doppler techniques, dynamic contrast-enhanced ultrasound and (shear wave) elastography.

RESULTS

Limited research available on combining ultrasound modalities has presented improvement in diagnostic performance. The data of two studies suggest that even adding a lower performing ultrasound modality to a better performing modality using crude methods can already improve the sensitivity by 13-51 %. The different modalities detect different tumours. No study has tried to combine ultrasound modalities employing a system similar to the PIRADS system used for mpMRI or more advanced classifying algorithms.

CONCLUSION

Available evidence confirms that combining different ultrasound modalities significantly improves diagnostic performance.

Dynamic contrast-enhanced ultrasound parametric imaging for the detection of prostate cancer

OBJECTIVE

To investigate the value of dynamic contrast-enhanced (DCE)-ultrasonography (US) and software-generated parametric maps in predicting biopsy outcome and their potential to reduce the amount of negative biopsy cores.

MATERIALS AND METHODS

For 651 prostate biopsy locations (82 consecutive patients) we correlated the interpretation of DCE-US recordings with and without parametric maps with biopsy results. The parametric maps were generated by software which extracts perfusion parameters that differentiate benign from malignant tissue from DCE-US recordings. We performed a stringent analysis (all tumours) and a clinical analysis (clinically significant tumours). We calculated the potential reduction in biopsies (benign on imaging) and the resultant missed positive biopsies (false-negatives). Additionally, we evaluated the performance in terms of sensitivity, specificity negative predictive value (NPV) and positive predictive value (PPV) on a per-prostate level.

RESULTS

Based on DCE-US, 470/651 (72.2%) of biopsy locations appeared benign, resulting in 40 false-negatives (8.5%), considering clinically significant tumours only. Including parametric maps, 411/651 (63.1%) of the biopsy locations appeared benign, resulting in 23 false-negatives (5.6%). In the per-prostate clinical analysis, DCE-US classified 38/82 prostates as benign, missing eight diagnoses. Including parametric maps, 31/82 prostates appeared benign, missing three diagnoses. Sensitivity, specificity, PPV and NPV were 73, 58, 50 and 79%, respectively, for DCE-US alone and 91, 56, 57 and 90%, respectively, with parametric maps.

CONCLUSION

The interpretation of DCE-US with parametric maps allows good prediction of biopsy outcome. A two-thirds reduction in biopsy cores seems feasible with only a modest decrease in cancer diagnosis.