Magnetic Resonance Imaging Prior to First Prostate Biopsy-Are we there yet?

Can a prostate biopsy be safely deferred on PI-RADS 1,2 or 3 lesions seen on pre-biopsy mp-MRI?

Introduction

Multi-parametric magnetic resonance imaging (mp-MRI) is currently used to triage patients with suspected prostate cancer, before deciding on prostate biopsies. In our study, we evaluated normal and equivocal pre-biopsy mp-MRIs to see whether it is safe to avoid biopsy with such findings.

Methods

A retrospective study was conducted at a district general hospital in the UK between August 2017 and July 2018. Patients with negative and equivocal prebiopsy mp-MRI with high clinical suspicion of cancer had proceeded to biopsy. MRI reports with prostate imaging reporting and data system (PI-RADS) scores 1, 2, 3 and normal MRI were evaluated against the transrectal ultrasound-guided prostate biopsy (TRUS-PB) outcomes to demonstrate benign pathology, clinically insignificant or clinically significant cancer (csCa). CsCa was defined as Gleason score (GS) ≥3 + 4.

Results

Out of 265 mp-MRIs studied, five (1.9%) were PI-RADS 1, 109 (41.1%) and 84 (31.7%) were PI-RADS 2 and 3 lesions respectively; 67 (25.3%) were reported as normal. Seventy-five (27.3%) patients did not have biopsies following their MRI and 73.3% (51/75) of them had benign feeling prostate. Negative MRIs (PI-RADS 1, 2 and normal MRI) showed 8.8% and PI-RADS 3 lesions demonstrated 11.9% csCa. Negative predictive value for normal MRI was 91.2%. Mean PSA density (PSAD) among the benign, GS 3 + 3 and csCa was 0.14, 0.16 and 0.27 ng/ml/ml respectively and this was statistically significant (p < 0.001). The average percentage of cancer found in GS 3 + 3 and csCa was 3.2% and 20.1%, respectively.

Conclusion

Avoiding TRUS-PB following normal or equivocal mp-MRI should carefully be decided as 18.5% of cancer was demonstrated in this group and 9.8% of those who were diagnosed with cancer were csCa. PSAD and DRE findings provide additional information to help with this decision.

Robotic-assisted transrectal MRI-guided biopsy. Technical feasibility and role in the current diagnosis of prostate cancer: an initial single-center experience

OBJECTIVES

To evaluate the potential clinical and technical utility to manage in practice the use of a robotic MRI in-bore-targeted prostate biopsies in the current work-up of prostate cancer diagnosis.

METHODS

Thirty patients with a single cancer suspicious lesion interpreted on MRI using PI-RADSv2.1 category ≥ 3 underwent in-bore robotic transrectal MRI remote-controlled-guided biopsy. It was analyzed the technical success, clinical details, biopsy findings in correlation with the MRI examination, complications and cancer detection rate (CDR).

RESULTS

The overall CDR for any cancer was 73% (22/30). It was 86% (19/22) for significant tumors (Gleason score of more than 6 or maximum cancer core length greater than 3 mm for Gleason 6) and 77% (17/22) for tumors with Gleason > 6. CDR for biopsy-naïve patients was 89% (16/18) and 50% (6/12) for patients with prior negative transrectal ultrasound-guided biopsies. The CDR for PI-RADS > 3 was 92% (22/24). All the lesions (n = 30) were reachable with the robotic MRI device. A self-limited rectal hemorrhagic complication was reported.

CONCLUSION

This initial data show that a robotic MRI-guided biopsy could be useful, efficient and feasible procedure in the new paradigm to diagnose significant prostate cancer in selected patients.

A Multicentre Analysis of the Detection of Clinically Significant Prostate Cancer Following Transperineal Image-fusion Targeted and Nontargeted Systematic Prostate Biopsy in Men at Risk

BACKGROUND

Prostate biopsy guided by magnetic resonance imaging (MRI) is increasingly used to obtain tissue from men with suspected prostate cancer (PC).

OBJECTIVE

To report a multicentre series of image-fusion transperineal prostate biopsies and compare the diagnostic yield of clinically significant PC (csPC) between targeted and nontargeted biopsies.

DESIGN, SETTING, AND PARTICIPANTS

The study included 640 consecutive patients with elevated prostate specific antigen (PSA) presenting for first biopsy or following a previous negative transrectal biopsy under the care of 13 urologists in 11 centres in the UK (April 2014-June 2017).

INTERVENTION

Multiparametric MRI was carried out in 61 approved prostate MRI centres with transperineal targeted alone (n=283) or targeted plus nontargeted (n=357) transperineal rigid image-fusion targeted biopsy (MIM-Symphony-DX).

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Rates of csPC and insignificant cancer detection in targeted and nontargeted biopsies were measured using a number of thresholds to define clinical significance. The primary definition was Gleason≥4+3 or any grade ≥6mm.

RESULTS AND LIMITATIONS

The mean age, median PSA, and median prostate volume for the cohort were 63.8yr (standard deviation [SD] 8.4), 6.3 ng/ml (SD 5.8), and 42.0cm3 (SD 24.7), respectively. Overall, 276/640 men (43.1%) were diagnosed with csPC. csPC was detected from targeted biopsies alone in 263/640 cases (41.1%). Of the 357 men who underwent nontargeted biopsies, three (0.8%) had csPC exclusively in nontargeted cores, with no evidence of cancer in targeted cores. Overall, 32/357 (9.0%) had csPC in nontargeted biopsies regardless of the targeted biopsy findings. Clinically insignificant disease in nontargeted biopsies was detected in 93/357 men (26.1%). Our findings were consistent across all other thresholds of clinical significance. Limitations include the lack of nontargeted biopsies in all men.

CONCLUSIONS

In this large multicentre series, nontargeted prostate biopsy cores had a low yield of csPC and a high yield of clinically insignificant PC. An image-fusion targeted-biopsy-only approach maintains high detection for csPC and low detection of clinically insignificant cancers.

PATIENT SUMMARY

In this report, we found that following prostate multiparametric magnetic resonance imaging and targeted transperineal biopsies of suspicious areas, the clinical value of performing additional extensive unguided biopsies of nonsuspicious areas is limited and can often find insignificant cancers that do not need treatment.

MRI-directed high-frequency (29MhZ) TRUS-guided biopsies: initial results of a single-center study

OBJECTIVES

To evaluate the ability of high-frequency (29 MHz) transrectal micro-ultrasound (microUS) as a second-look examination after biparametric MRI (bp-MRI) and to reidentify focal lesions seen on diagnostic MRI and to detect new ones METHODS: A total of 118 consecutive men (mean age, 66 ± 13 [SD] years; range, 49-93 years) with a mean prostate-specific antigen level of 11 ± 19 (SD) ng/mL (range, 2-200 ng/mL) and at least one focal lesion (MRI+) with a score > 2 on bp-MRI were included. Of these, 79/118 (66.9%) were biopsy-naïve and 102/118 (86.5%) had non-suspicious rectal examination. All patients had MRI-directed microUS-guided biopsy using a 29-MHz transducer. All lesions visible on micro-ultrasound (microUS+) were targeted without image fusion, which was only used for MRI+/microUS- lesions. Significant prostate cancer (sPCa) was defined by a Gleason score ≥ 7 or a maximum cancer core length > 3 mm.

RESULTS

A total of 144 focal prostatic lesions were analyzed, including 114 (114/144, 79.2%) MRI+/microUS+ lesions, 13 MRI+/microUS- lesions (13/144, 9%), and 17 MRI-/microUS+ lesions (17/144, 11.8%). Significant PCa was detected in 70 MRI+/microUS+ lesions (70/114, 61.4%), in no MRI+/microUS- lesion (0/13, 0%), and in 4 MRI-/microUS+ lesions (4/17, 23.5%). The sensitivity and specificity of microUS on a per-patient and a per-lesion basis were 100% (95% CI, 84.9-100%) and 22.8% (95% CI, 12.5-35.8%) and 100% (95% CI, 85.1-100%) and 22.6% (95% CI, 12.3-36.2%), respectively.

CONCLUSION

MicroUS, as a second-look examination, may show promise to localize targets detected on bp-MRI.

KEY POINTS

• Used as a second-look examination, microUS-guided biopsies have a 100% detection rate of sCa originating in the PZ or lower third of the TZ, without microUS-MRI image fusion. • MicroUS results may provide additional information about lesions visible on MRI. • MicroUS may provide the ability to detect small PZ lesions undetected by bp-MRI.

Adverse pathology after radical prostatectomy: the prognostic role of cumulative cancer length >6-mm threshold in prostate cancer-positive biopsies

Background

To investigate the role of Cumulative Cancer Length (CCL) and PCa positive core number (PCapcn) in random prostate biopsies as predictors of Adverse Pathology (AP) at definitive pathology.

Methods

We prospectively enrolled patients submitted to random ultrasound guided prostate biopsies for suspect PCa in our center since 2016. Inclusion criteria were PSA <20 ng/ml or >3 ng/ml and age<71 years. Data on CCL and Grade Group (GG) at biopsy and pathology after Radical Prostatectomy (RP) were collected. AP was defined as pT3 or higher TNM, Positive Surgical Margin (>2mm) or PCa Positive Lymph Node. ROC curve was used to establish an appropriate CCL and PCapcn thresholds that were then investigated as predictors of AP at definitive pathology.

Results

Among 882 eligible biopsies, 344 had PCa and underwent RP. Mean age was 64 years (SD 5). Mean PSA was 7.75 (SD: 3.66). At definitive pathology there were AP features in 196 (56.9%) RP. PCapcn and CCL were statistically significantly associated with AP (p<0.0001). At multivariate age-adjusted logistic regression only PCapcn had an OR of 1.513 (CI95% 1.140-2.007) p=0.004. Through ROC curve a CCL>6mm and PCapcn >3 thresholds for AP were established (Area: 0.769; p<0.0001 CI 95% 0.698-0.840 and Area: 0.767; p<0.0001 CI 95% 0.696-0.837). When considering CCL>6mm AP had OR 5.462 (CI 95% 2.717-10.978) p<0.0001 and PCapcn >3 had OR 7.127 (CI 95% 3.366-15.090) p<0.0001. In particular, for GG 1 and 2, CCL>6mm had OR 3.989 (CI 95% 1.839-8.652) p<0.0001, while PCapcn >3 had OR 5.541 (CI 95% 2.390-12.849) p<0.0001.

Conclusions

At present time, random prostate biopsies might carry useful information regarding tumor extension and aggressiveness. A CCL>6mm or PCapcn >3 might be associated with AP features, in particular for low and favorable intermediate risk PCa.

Accuracy of Tumour-Associated Circulating Endothelial Cells as a Screening Biomarker for Clinically Significant Prostate Cancer

Even though more than 350,000 men die from prostate cancer every year, broad-based screening for the disease remains a controversial topic. Guidelines demand that the only commonly accepted screening tool, prostate-specific antigen (PSA) testing, must be followed by prostate biopsy if results are elevated. Due to the procedure’s low positive predictive value (PPV), however, over 80% of biopsies are performed on healthy men or men with clinically insignificant cancer—prompting calls for new ways of vetting equivocal PSA readings prior to the procedure. Responding to the challenge, the present study investigated the diagnostic potential of tumour-associated circulating endothelial cells (tCECs), which have previously been described as a novel, blood-based biomarker for clinically significant cancers. Specifically, the objective was to determine the diagnostic accuracy of a tCEC-based blood test to detect clinically significant prostate cancer (defined as Gleason score ≥ 3 + 4) in high-risk patients. Performed in a blinded, prospective, single-centre set-up, it compared a novel tCEC index test with transrectal ultrasound-guided biopsy as a reference on a total of 170 patients and found that a tCEC add-on test will almost double the PPV of a standalone PSA test (32% vs. 17%; p = 0.0012), while retaining a negative predictive value above 90%.

Applying the PRECISION approach in biopsy naïve and previously negative prostate biopsy patients

OBJECTIVES

The PRECISION trial provides level 1 evidence supporting prebiopsy multiparametric magnetic resonance imaging (mpMRI) followed by targeted biopsy only when mpMRI is abnormal [1]. This approach reduced over-detection of low-grade cancer while increasing detection of clinically significant cancer (CSC). Still, important questions remain regarding the reproducibility of these findings outside of a clinical trial and quantifying missed CSC diagnoses using this approach. To address these issues, we retrospectively applied the PRECISION strategy in men who each underwent prebiopsy mpMRI followed by systematic and targeted biopsy.

METHODS AND MATERIALS

Clinical, imaging, and pathology data were prospectively collected from 358 biopsy naïve men and 202 men with previous negative biopsies. To apply the PRECISION approach, a retrospective analysis was done comparing the cancer yield from 2 diagnostic strategies: (1) mpMRI followed by targeted biopsy alone for men with Prostate Imaging Reporting and Data System ≥ 3 lesions and (2) systematic biopsy alone for all men. Primary outcomes were biopsies avoided and the proportion of CSC cancer (Grade Group 2-5) and non-CSC (Grade Group 1).

RESULTS

In biopsy naïve patients, the mpMRI diagnostic strategy would have avoided 19% of biopsies while detecting 2.5% more CSC (P= 0.480) and 12% less non-CSC (P< 0.001). Thirteen percent (n= 9) of men with normal mpMRI had CSC on systematic biopsy. For previous negative biopsy patients, the mpMRI diagnostic strategy avoided 21% of biopsies, while detecting 1.5% more CSC (P= 0.737) and 13% less non-CSC (P< 0.001). Seven percent (n= 3) of men with normal mpMRI had CSC on systematic biopsy.

CONCLUSIONS

Our results provide external validation of the PRECISION finding that mpMRI followed by targeted biopsy of suspicious lesions reduces biopsies and over-diagnosis of low-grade cancer. Unlike PRECISION, we did not find increased diagnosis of CSC. This was true in both biopsy naïve and previously negative biopsy cohorts. We have incorporated this information into shared decision making, which has led some men to choose to avoid biopsy. However, we continue to recommend targeted and systematic biopsy in men with abnormal MRI.