[Value of MRI/ultrasound fusion in primary biopsy for the diagnosis of prostate cancer]

[Fusion biopsies for primary diagnosis of prostate cancer : Implementation, benefits, and clinical aspects]

Prostate carcinoma is one of the most common tumors worldwide. Histological confirmation by biopsy is an obligatory part of the diagnostic approach. The main problem of the 10-12-fold transrectal ultrasound-guided (TRUS) biopsy, which has so far been regarded as the gold standard, is the underdiagnosis of clinically significant cancer. MRI-based procedures, so-called fusion biopsies, have shown superior results when compared to conventional biopsies. There are three different approaches (cognitive and software-based MRI/TRUS fusion and in-bore biopsy) with comparable detection rates but differences in the technical aspects and time involvement. In order to reduce fusion errors, targeted biopsies should consist of multiple cores. There is currently no clear preference for the access pathway (transrectal or transperineal), but clinical parameters such as infection risk or location of the tumor can influence the decision. While the German S3 guideline considers MRI prior to primary biopsy to be optional, the 2019 European Association of Urology guidelines already recommend MRI prior to biopsy for all patients. The combination of MRI-targeted and systematic biopsy offers the highest detection rates with the disadvantage that more low-risk tumors are diagnosed. Both the patient and the urologist benefit from an improved informative value of the biopsy when deciding on active surveillance as well as when planning invasive therapies.

Accuracy of the magnetic resonance imaging pathway in the detection of prostate cancer: a systematic review and meta-analysis

BACKGROUND

Although magnetic resonance imaging and subsequent targeted biopsy ('MRI pathway') have been widely adopted in routine clinical practice, it is still a common practice to perform systematic biopsy concurrently, because the accuracy of the MRI pathway is yet to be fully defined. This systematic review of the literature assessed the sensitivity of the MRI pathway for detecting clinically significant prostate cancer.

METHODS

Multiple databases were searched up to May 2017 according to the Preferred Reporting Items for Systematic Review and Meta-analysis (PRISMA) statement for studies assessing the accuracy of MR-guided biopsy (MRGB) compared to a reference standard which consisted of both MRGB and systematic biopsy with at least 20-cores. The primary outcome was the sensitivity of detecting clinically significant prostate cancer defined as Gleason ≥7 disease.

RESULTS

A total of 15 studies met the predefined inclusion criteria. Overall, studies were assessed to be of low quality with inadequate blinding of personnel, which could introduce performance and detection bias. The calculated summary sensitivity of the MRI pathway was 78.3% [95%CI 75.0-81.4%]. There was moderate heterogeneity between the included studies (I² = 36%). Subgroup analysis was performed based on clinical setting, the strength of MRI magnet and mode of image fusion as factors but no interaction was identified between any of the subgroups. No publication bias was identified.

CONCLUSION

The MRI pathway cannot yet be solely relied upon to diagnose clinically significant disease and hence additional systematic sampling should still be performed during the biopsy procedure.

[MRI/TRUS fusion-guided prostate biopsy : Value in the context of focal therapy]

BACKGROUND

Several systems for MRI/TRUS fusion-guided biopsy of the prostate are commercially available. Many studies have shown superiority of fusion systems for tumor detection and diagnostic quality compared to random biopsy. The benefit of fusion systems in focal therapy of prostate cancer (PC) is less clear.

OBJECTIVES

Critical considerations of fusion systems for planning and monitoring of focal therapy of PC were investigated.

MATERIALS AND METHODS

A systematic literature review of available fusion systems for the period 2013-5/2016 was performed. A checklist of technical details, suitability for special anatomic situations and suitability for focal therapy was established by the German working group for focal therapy (Arbeitskreis fokale und Mikrotherapie).

RESULTS

Eight fusion systems were considered (Artemis™, BioJet, BiopSee®, iSR´obot™ Mona Lisa, Hitachi HI-RVS, UroNav and Urostation®). Differences were found for biopsy mode (transrectal, perineal, both), fusion mode (elastic or rigid), navigation (image-based, electromagnetic sensor-based or mechanical sensor-based) and space requirements.

DISCUSSION

Several consensus groups recommend fusion systems for focal therapy. Useful features are "needle tracking" and compatibility between fusion system and treatment device (available for Artemis™, BiopSee® and Urostation® with Focal One®; BiopSee®, Hitachi HI-RVS with NanoKnife®; BioJet, BiopSee® with cryoablation, brachytherapy).

CONCLUSIONS

There are a few studies for treatment planning. However, studies on treatment monitoring after focal therapy are missing.

[Diagnostic significance of multiparametric MRI combined with US-fusion guided biopsy of the prostate in patients with increased PSA levels and negative standard biopsy results to detect significant prostate cancer - Correlation with the Gleason score. Korrelation mit dem Gleason Score]

AIMS

To increase diagnostic precision and to reduce overtreatment of low-risk malignant disease, multiparametric MRI (mpMRI) combined with ultrasound (US) fusion guided biopsy of the prostate were performed.

METHODS

In 99 male patients with increased PSA plasma levels and previous negative standard biopsy procedures, mpMRI was carried out followed by US fusion guided perineal biopsy. PI-RADS-Data (PS) of mpMRI and histopathological Gleason score (GS) were categorized and statistically compared.

RESULTS

Lesions in 72/99 (73 %) of patients were determined to be suspect of malignancy, based on a PS 4 or 5. In 33/99 (33 %) of patients, malignancy could not be confirmed by histopathology. With regard to the remaining 66 patients with previous negative biopsy results, 42 (64 %) were diagnosed with a low-grade carcinoma (GS 6, 7a) and 24 (36 %) with a high-grade carcinoma (GS ≥ 7b). The proportion of corresponding results in mpMRI (PS 4-5) when a high-grade carcinoma had been detected, was 21/24 (88 %), which related to a sensitivity of 88 % and a negative predictive value (NPV) of 85 % (p = 0,002). In addition, 35 of 42 patients (83%), graded PS 4-5 in mpMRI, were diagnosed with low-grade carcinoma-positive (p < 0,001). Sensitivity to differentiation between low- and high-grade carcinomas (GS ≤ 7a vs. ≥ 7b) by means of PS was 88 % with a NPV of 70 % (p = 0,74).

CONCLUSION

Our results suggest that mpMRI combined with US-fusion guided biopsy is able to detect considerably higher rates of clinically relevant prostate malignancies compared to conventional diagnostic procedures. However, no statistical significance could be shown regarding the differentiation between high- and low-grade carcinomas. It is hoped that the hybrid methods PSMA-PET/CT or PSMA-PET/MRI will lead to the next optimization step in the differentiation between high- and low-grade carcinomas which so far has been unsatisfactory.

The addition of a sagittal image fusion improves the prostate cancer detection in a sensor-based MRI /ultrasound fusion guided targeted biopsy

BACKGROUND

To explore the diagnostic benefit of an additional image fusion of the sagittal plane in addition to the standard axial image fusion, using a sensor-based MRI/US fusion platform.

METHODS

During July 2013 and September 2015, 251 patients with at least one suspicious lesion on mpMRI (rated by PI-RADS) were included into the analysis. All patients underwent MRI/US targeted biopsy (TB) in combination with a 10 core systematic prostate biopsy (SB). All biopsies were performed on a sensor-based fusion system. Group A included 162 men who received TB by an axial MRI/US image fusion. Group B comprised 89 men in whom the TB was performed with an additional sagittal image fusion.

RESULTS

The median age in group A was 67 years (IQR 61-72) and in group B 68 years (IQR 60-71). The median PSA level in group A was 8.10 ng/ml (IQR 6.05-14) and in group B 8.59 ng/ml (IQR 5.65-12.32). In group A the proportion of patients with a suspicious digital rectal examination (DRE) (14 vs. 29%, p = 0.007) and the proportion of primary biopsies (33 vs 46%, p = 0.046) were significantly lower. The rate of PI-RADS 3 lesions were overrepresented in group A compared to group B (19 vs. 9%; p = 0.044). Classified according to PI-RADS 3, 4 and 5, the detection rates of TB were 42, 48, 75% in group A and 25, 74, 90% in group B. The rate of PCa with a Gleason score ≥7 missed by TB was 33% (18 cases) in group A and 9% (5 cases) in group B; p-value 0.072. An explorative multivariate binary logistic regression analysis revealed that PI-RADS, a suspicious DRE and performing an additional sagittal image fusion were significant predictors for PCa detection in TB. 9 PCa were only detected by TB with sagittal fusion (sTB) and sTB identified 10 additional clinically significant PCa (Gleason ≥7).

CONCLUSION

Performing an additional sagittal image fusion besides the standard axial fusion appears to improve the accuracy of the sensor-based MRI/US fusion platform.

Assessment of the Performance of Magnetic Resonance Imaging/Ultrasound Fusion Guided Prostate Biopsy against a Combined Targeted Plus Systematic Biopsy Approach Using 24-Core Transperineal Template Saturation Mapping Prostate Biopsy

Objective. To compare the performance of multiparametric resonance imaging/ultrasound fusion targeted biopsy (MRI/US-TBx) to a combined biopsy strategy (MRI/US-TBx plus 24-core transperineal template saturation mapping biopsy (TTMB)). Methods. Between May 2012 and October 2015, all patients undergoing MRI/US-TBx at our institution were included for analysis. Patients underwent MRI/US-TBx of suspicious lesions detected on multiparametric MRI +/− simultaneous TTMB. Subgroup analysis was performed on patients undergoing simultaneous MRI/US-TBx + TTMB. Primary outcome was PCa detection. Significant PCa was defined as ≥Gleason score (GS) 3 + 4 = 7 PCa. McNemar's test was used to compare detection rates between MRI/US-TBx and the combined biopsy strategy. Results. 148 patients underwent MRI/US-TBx and 80 patients underwent MRI/US-TBx + TTMB. In the MRI/US-TBx versus combined biopsy strategy subgroup analysis (n = 80), there were 55 PCa and 38 significant PCa. The detection rate for the combined biopsy strategy versus MRI/US-TBx for significant PCa was 49% versus 40% (p = 0.02) and for insignificant PCa was 20% versus 10% (p = 0.04), respectively. Eleven cases (14%) of significant PCa were detected exclusively on MRI/US-TBx and 7 cases (8.7%) of significant PCa were detected exclusively on TTMB. Conclusions. A combined biopsy approach (MRI/US-TBx + TTMB) detects more significant PCa than MRI/US-TBx alone; however, it will double the detection rate of insignificant PCa.