Repeat prostate biopsy and the incremental risk of clinically insignificant prostate cancer

Core Needle Biopsy Guidance Based on Tissue Morphology Assessment with AI-OCT Imaging

This paper presents a combined optical imaging/artificial intelligence (OI/AI) technique for the real-time analysis of tissue morphology at the tip of the biopsy needle, prior to collecting a biopsy specimen. This is an important clinical problem as up to 40% of collected biopsy cores provide low diagnostic value due to high adipose or necrotic content. Micron-scale-resolution optical coherence tomography (OCT) images can be collected with a minimally invasive needle probe and automatically analyzed using a computer neural network (CNN)-based AI software. The results can be conveyed to the clinician in real time and used to select the biopsy location more adequately. This technology was evaluated on a rabbit model of cancer. OCT images were collected with a hand-held custom-made OCT probe. Annotated OCT images were used as ground truth for AI algorithm training. The overall performance of the AI model was very close to that of the humans performing the same classification tasks. Specifically, tissue segmentation was excellent (~99% accuracy) and provided segmentation that closely mimicked the ground truth provided by the human annotations, while over 84% correlation accuracy was obtained for tumor and non-tumor classification.

A novel phage display based platform for exosome diversity characterization

We present an innovative approach allowing the identification, isolation, and molecular characterization of disease-related exosomes based on their different antigenic reactivities. The designed strategy could be immediately translated into any disease in which exosomes are involved. The identification of specific markers and their subsequent association with exosome subtypes, together with the possibility to engineer target-guided exosome-like particles, could represent the key for the effective adoption of exosomes in clinical practice.

In-bore MRI-guided prostate biopsy in a patient group with PI-RADS 4 and 5 targets: A single center experience

PURPOSE

To determine the diagnostic yield of magnetic resonance imaging (MRI) guided in-bore biopsy in patients with high likelihood multiparametric MRI (mpMRI) findings, regarding overall and clinically significant prostate cancer (csPCa) detection rates and concordance of biopsy and radical prostatectomy (RP) Gleason scores (GS).

METHODS

This retrospective study consisted of 277 Prostate Imaging Reporting and Data System (PI-RADS) assessment category 4 and 5 targets in 246 patients (mean age, 65.7 years; median prostate specific antigen value, 7.75 ng/mL) who had undergone in-bore biopsy at our institution between 2012 and 2020. Eighty-one patients who underwent RP were eligible for the concordance analysis of biopsy and RP specimen GS.

RESULTS

Overall PCa detection rates were 80.5 % per patient (198/246) and 78 % per target (216/277) and 83.5 % and 67.4 % in primary (biopsy naive) and secondary (at least one negative prior biopsy) settings. csPCa was found in 63 % overall, 66 % of patients (132/200) in the primary, and 50 % of patients (23/46) in the secondary biopsy settings (p < 0.001). The prostate cancer detection rate was 68 % and 92 % in PI-RADS 4 and 5, respectively (p < 0.001). In the radical prostatectomy subcohort, 27.2 % of patients were upgraded, 8.6 % of patients were downgraded from needle biopsy. Significant complications occurred in 1.2 % of patients.

CONCLUSIONS

MRI-guided in-bore prostate biopsy has a high detection rate of csPCa in primary and secondary biopsy cohorts. Biopsy results were satisfactory in terms of the number of positive cores, cancer percentage in positive cores, and concordance of GS in needle biopsy and RP specimen.

[Intelligent early prostate cancer detection in 2021: more benefit than harm]

Prostate-specific antigen (PSA) is used for early detection of prostate cancer which represents the most frequent cancer diagnosed in men in Germany and Europe. Results of the largest screening trials revealed that PSA testing reduces the incidence of locally advanced and metastatic prostate cancer and shows an effect on cancer-specific mortality. However, since early diagnosis also results in overdiagnosis and overtreatment of insignificant cancers with associated morbidities, there is a need for a more individualized and risk-tailored modern strategy. The PSA at baseline is an important part of this strategy although the German Federal Joint Committee declined its financial coverage by health insurances. Available validated instruments should accompany the baseline PSA to optimize detection of clinically significant prostate cancer.

Evaluation of an Epigenetic Assay for Predicting Repeat Prostate Biopsy Outcome in African American Men

OBJECTIVE

To evaluate an epigenetic assay performed on tissue from negative prostate biopsies in a group of African American (AA) men undergoing repeat biopsy, and to compare accuracy for predicting repeat biopsy outcome to prior studies conducted in predominantly Caucasian populations.

MATERIALS AND METHODS

The study population consisted of 211 AA men from 7 urology centers across the United States; all of whom were undergoing 12-core transrectal ultrasound-guided repeat biopsy within 30 months from a negative index biopsy. All biopsy cores from the negative index biopsy were profiled for the epigenetic biomarkers GSTP1, APC, and RASSF1 using ConfirmMDx for Prostate Cancer (MDxHealth, Irvine, CA).

RESULTS

Upon repeat biopsy, 130 of 211 subjects (62%) had no prostate cancer (PCa) detected and 81 of 211 (38%) were diagnosed with PCa. Of the subjects with PCa, 54 (67%) were diagnosed with Gleason score (GS) ≤6 PCa and 27 (33%) with GS ≥7 disease. For detection of PCa at repeat biopsy, ConfirmMDx sensitivity was 74.1% and specificity was 60.0%, equivalent to prior studies (P = .235 and .697, respectively). For detection of GS ≥7 PCa, sensitivity was 78% and specificity was 53%. The negative predictive values for detection of all PCa and GS ≥7 PCa were 78.8% and 94.2%, respectively.

CONCLUSION

In this group of AA men, we successfully validated an epigenetic assay to assess the need for repeat biopsy. Results were consistent with previous studies from predominantly Caucasian populations. Therefore, the ConfirmMDx assay is a useful tool for risk stratification of AA men who had an initial negative biopsy.

Epigenetic risk score improves prostate cancer risk assessment

BACKGROUND

Early detection of aggressive prostate cancer (PCa) remains crucial for effective treatment of patients. However, PCa screening remains controversial due to a high rate of overdiagnosis and overtreatment. To better reconcile both objectives, more effective methods for assessing disease severity at the time of diagnosis are needed.

METHODS

The relationship between DNA-methylation and high-grade PCa was examined in a cohort of 102 prospectively enrolled men who received standard 12-core prostate biopsies. EpiScore, an algorithm that quantifies the relative DNA methylation intensities of GSTP1, RASSF1, and APC in prostate biopsy tissue, was evaluated as a method to compensate for biopsy under-sampling and improve risk stratification at the time of diagnosis.

RESULTS

DNA-methylation intensities of GSTP1, RASSF1, and APC were higher in biopsy cores from men diagnosed with GS ≥ 7 cancer compared to men with diagnosed GS 6 disease. This was confirmed by EpiScore, which was significantly higher for subjects with high-grade biopsies and higher NCCN risk categories (both P < 0.001). In patients diagnosed with GS ≥ 7, increased levels of DNA-methylation were present, not only in the high-grade biopsy cores, but also in other cores with no or low-grade disease (P < 0.001). By combining EpiScore with traditional clinical risk factors into a logistic regression model, the prediction of high GS reached an AUC of 0.82 (95%CI: 0.73-0.91) with EpiScore, DRE, and atypical histological findings as most important contributors.

CONCLUSIONS

In men diagnosed with PCa, DNA-methylation profiling can detect under-sampled high-risk PCa in prostate biopsy specimens through a field effect. Predictive accuracy increased when EpiScore was combined with other clinical risk factors. These results suggest that EpiScore could aid in the detection of occult high-grade disease at the time of diagnosis, thereby improving the selection of candidates for Active Surveillance.

MR Safe Robot, FDA Clearance, Safety and Feasibility Prostate Biopsy Clinical Trial

Compatibility of mechatronic devices with the MR environment has been a very challenging engineering task. After over a decade of developments, we report the successful translation to clinical trials of our MR Safe robot technology. MrBot is a 6-degree-of-freedom, pneumatically actuated robot for transperineal prostate percutaneous access, built exclusively of electrically nonconductive and nonmagnetic materials. Its extensive pre-clinical tests have been previously reported. Here, we present the latest technology developments, an overview of the regulatory protocols, and technically related results of the clinical trial. The FDA has approved the MrBot for the biopsy trial, which was successfully performed in 5 patients. With no trajectory corrections, and no unsuccessful attempts to target a site, the robot achieved an MRI based needle targeting accuracy of 2.55 mm. To the best of our knowledge, this is the first robot approved by the FDA for the MR environment. The results confirm that it is possible to perform safe and accurate robotic manipulation in the MRI scanner, and the development of MR Safe robots is no longer a daunting technical challenge.

Development and External Validation of the Korean Prostate Cancer Risk Calculator for High-Grade Prostate Cancer: Comparison with Two Western Risk Calculators in an Asian Cohort

PURPOSE

We developed the Korean Prostate Cancer Risk Calculator for High-Grade Prostate Cancer (KPCRC-HG) that predicts the probability of prostate cancer (PC) of Gleason score 7 or higher at the initial prostate biopsy in a Korean cohort (http://acl.snu.ac.kr/PCRC/RISC/). In addition, KPCRC-HG was validated and compared with internet-based Western risk calculators in a validation cohort.

MATERIALS AND METHODS

Using a logistic regression model, KPCRC-HG was developed based on the data from 602 previously unscreened Korean men who underwent initial prostate biopsies. Using 2,313 cases in a validation cohort, KPCRC-HG was compared with the European Randomized Study of Screening for PC Risk Calculator for high-grade cancer (ERSPCRC-HG) and the Prostate Cancer Prevention Trial Risk Calculator 2.0 for high-grade cancer (PCPTRC-HG). The predictive accuracy was assessed using the area under the receiver operating characteristic curve (AUC) and calibration plots.

RESULTS

PC was detected in 172 (28.6%) men, 120 (19.9%) of whom had PC of Gleason score 7 or higher. Independent predictors included prostate-specific antigen levels, digital rectal examination findings, transrectal ultrasound findings, and prostate volume. The AUC of the KPCRC-HG (0.84) was higher than that of the PCPTRC-HG (0.79, p<0.001) but not different from that of the ERSPCRC-HG (0.83) on external validation. Calibration plots also revealed better performance of KPCRC-HG and ERSPCRC-HG than that of PCPTRC-HG on external validation. At a cut-off of 5% for KPCRC-HG, 253 of the 2,313 men (11%) would not have been biopsied, and 14 of the 614 PC cases with Gleason score 7 or higher (2%) would not have been diagnosed.

CONCLUSIONS

KPCRC-HG is the first web-based high-grade prostate cancer prediction model in Korea. It had higher predictive accuracy than PCPTRC-HG in a Korean population and showed similar performance with ERSPCRC-HG in a Korean population. This prediction model could help avoid unnecessary biopsy and reduce overdiagnosis and overtreatment in clinical settings.

Patterns of repeat prostate biopsy in contemporary clinical practice

PURPOSE

The objectives of this study were to 1) describe the patterns of repeat prostate biopsy in men with a previous negative biopsy and 2) identify predictors of prostate cancer diagnosis on repeat biopsy in these men.

MATERIALS AND METHODS

From a university faculty group practice we identified 1,837 men who underwent prostate biopsy between January 1, 1995 and January 1, 2010. Characteristics of repeat biopsy were examined, including the indication for biopsy, the number of repeat biopsies performed, the number of cores obtained and total prostate specific antigen before biopsy. Features of prostate cancer diagnosed on repeat biopsy were examined, including Gleason score, number of positive cores, percent of tumor and treatment choice. Multivariable logistic regression was done to identify prostate cancer predictors.

RESULTS

Initial biopsy was negative in 1,213 men. In 255 men a total of 798 repeat biopsies were performed. Of the 63 men diagnosed with prostate cancer Gleason score was 6 or less in 33 (52%), 7 in 22 (35%) and 8-9 in 8 (13%). When categorized by Epstein criteria, the rate of clinically insignificant cancer diagnosis decreased substantially by the third and fourth repeat biopsies. Repeat biopsy in men older than 70 years, biopsies including more than 20 cores and the fourth repeat biopsy were associated with an increased likelihood of prostate cancer diagnosis.

CONCLUSIONS

In men selected for multiple repeat biopsies clinically significant cancer is found at each sampling round. Given the continued likelihood of cancer detection even by the fifth biopsy, early consideration of saturation or image guided biopsy may be warranted in the repeat biopsy population.

Standards for prostate biopsy

PURPOSE OF REVIEW

A variety of techniques have emerged for the optimization of prostate biopsy. In this review, we summarize and critically discuss the most recent developments regarding the optimal systematic biopsy and sampling labeling along with multiparametric MRI and magnetic resonance-targeted biopsies.

RECENT FINDINGS

The use of 10-12-core-extended sampling protocols increases cancer detection rates compared with traditional sextant sampling and reduces the likelihood that patients will require a repeat biopsy, ultimately allowing more accurate risk stratification without increasing the likelihood of detecting insignificant cancers. As the number of cores increases above 12 cores, the increase in diagnostic yield becomes marginal. However, the limitations of this technique include undersampling, oversampling, and the need for repetitive biopsy. MRI and magnetic resonance-targeted biopsies have demonstrated superiority over systematic biopsies for the detection of clinically significant disease and representation of disease burden, while deploying fewer cores and may have applications in men undergoing initial or repeat biopsy and those with low-risk cancer on or considering active surveillance.

SUMMARY

A 12-core systematic biopsy that incorporates apical and far-lateral cores in the template distribution allows maximal cancer detection, avoidance of a repeat biopsy while minimizing the detection of insignificant prostate cancers. MRI-guided prostate biopsy has an evolving role in both initial and repeat prostate biopsy strategies, as well as active surveillance, potentially improving sampling efficiency, increasing the detection of clinically significant cancers, and reducing the detection of insignificant cancers.

Multiple repeat prostate biopsies and the detection of clinically insignificant cancer in men with large prostates

OBJECTIVE

To determine the impact of repeating prostate biopsies on the risk of detecting clinically insignificant prostate cancer (PCa) in larger prostate glands.

METHODS

We performed a retrospective cohort study using patients enrolled in our institutional PCa registry from 1991 to 2008 to assess the association of prostate volume and clinically insignificant PCa in men undergoing multiple prostate biopsies. Patients were stratified by prostate volume into 2 cohorts (<50 cm(3) or ≥50 cm(3)). Additionally, patients were stratified by prostate biopsy on which PCa was identified (1 biopsy or ≥3 biopsies).

RESULTS

Within the subgroup of patients with prostate volume ≥50 cm(3) requiring ≥3 biopsies before cancer diagnosis, 72.6% (45/62) had pathologic Gleason scores ≤6 and 81.6% (49/60) had an estimated tumor volume of ≤10% at the time of radical prostatectomy. This was significantly different from patients with prostate volume <50 cm(3) diagnosed on their first biopsy, in which only 48.5% (656/1349) were found to have Gleason scores ≤6 and 54.2% (705/1300) had estimated tumor volume ≤10% (P <.01). There was no significant difference in the rate of Gleason score upgrading at time of prostatectomy between any of the subgroups.

CONCLUSION

PCas detected in men with prostatic enlargement requiring multiple biopsies are more likely to be low-grade, low-volume tumors at final pathology than men without prostate enlargement. Men with larger prostates who have already had prior negative biopsies should be counseled regarding the increased risk of detecting clinically insignificant PCa with additional biopsies.

Overdiagnosis and overtreatment of prostate cancer

CONTEXT

Although prostate cancer (PCa) screening reduces the incidence of advanced disease and mortality, trade-offs include overdiagnosis and resultant overtreatment.

OBJECTIVE

To review primary data on PCa overdiagnosis and overtreatment.

EVIDENCE ACQUISITION

Electronic searches were conducted in Cochrane Central Register of Controlled Trials, PubMed, and Embase from inception to July 2013 for original articles on PCa overdiagnosis and overtreatment. Supplemental articles were identified through hand searches.

EVIDENCE SYNTHESIS

The lead-time and excess-incidence approaches are the main ways used to estimate overdiagnosis in epidemiological studies, with estimates varying widely. The estimated number of PCa cases needed to be diagnosed to save a life has ranged from 48 down to 5 with increasing follow-up. In clinical studies, generally lower rates of overdiagnosis have been reported based on the frequency of low-grade minimal tumors at radical prostatectomy (1.7-46.8%). Autopsy studies have reported PCa in 18.5-38.5%, although not all are low grade or low volume. Factors influencing overdiagnosis include the study population, screening protocol, and background incidence, limiting generalizability between settings. Reported rates of overtreatment vary widely in the literature, although contemporary international studies suggest increasing use of conservative management.

CONCLUSIONS

Epidemiological, clinical, and autopsy studies have been used to examine PCa overdiagnosis, with estimates ranging widely from 1.7% to 67%. Correspondingly, estimates of overtreatment vary widely based on patient features and may be declining internationally. Careful patient selection for screening and reducing overtreatment are important to preserve the benefits and reduce the downstream harms of prostate-specific antigen testing. Because all of these estimates are extremely population and context specific, this must be considered when using these data to inform policy.

PATIENT SUMMARY

Screening reduces spread and death from prostate cancer (PCa) but overdiagnoses some low-risk tumors that may not have caused harm. Because treatment has potential side effects, it is critical that not all patients with PCa receive aggressive treatment.

Application of (99m)Technetium-HYNIC(tricine/TPPTS)-Aca-Bombesin(7-14) SPECT/CT in prostate cancer patients: a first-in-man study

RATIONALE

The peptide bombesin (BBN) and its derivatives exhibit high binding affinity for the gastrin-releasing peptide receptor (GRPR), which is highly expressed in prostate cancer. We used the BBN-based radiopharmaceutical (99m)Technetium-HYNIC(tricine/TPPTS)-Aca-Bombesin(7-14) ((99m)Tc-HABBN) to perform a first-in-man clinical pilot study to evaluate the feasibility of (99m)Tc-HABBN SPECT/CT for detection of prostate cancer in patients.

METHODS

Eight patients with biopsy-proven prostate cancer who were scheduled for either radical prostatectomy or external beam radiotherapy underwent (99m)Tc-HABBN scintigraphy and SPECT/CT prior to treatment. Serial blood samples were taken to assess blood radioactivity and to determine in vivo metabolic stability. Clinical parameters were measured and reported side effects, if present, were recorded. Prostate cancer specimens of all patients were immunohistochemically stained for GRPR.

RESULTS

(99m)Tc-HABBN was synthesized with high radiochemical yield, purity and specific activity. There were no significant changes in clinical parameters, and there were no adverse or subjective side effects. Low metabolic stability was observed, as less than 20% of (99m)Tc-HABBN was intact after 30 min. Immunohistochemical staining for GRPR was observed in the prostate cancer specimens in all patients. (99m)Tc-HABBN scintigraphy and SPECT/CT did not detect prostate cancer in patients with proven disease.

CONCLUSIONS

(99m)Tc-HABBN SPECT/CT for visualization of prostate cancer is safe but hampered by an unexpected low in vivo metabolic stability in man. The difference between the excellent in vitro stability of (99m)Tc-HABBN in human serum samples determined in our previous study regarding (99m)Tc-HABBN and the low in vivo metabolic stability determined in this study, is striking. This issue warrants further study of peptide-based radiopharmaceuticals.

Many young men with prostate-specific antigen (PSA) screen-detected prostate cancers may be candidates for active surveillance

WHAT'S KNOWN ON THE SUBJECT? AND WHAT DOES THE STUDY ADD?: Little is known as to the potential for over-treatment of young men diagnosed with prostate cancer. We show that for men aged ≤55 years with PSA screen-detected disease, 45% of the tumours are classified as very low risk and 85% of these have favourable pathology, yet most are actively treated. These findings raise the spectre of over-treatment for a group of men likely to be affected by treatment side-effects.

OBJECTIVE

To identify a population of young men (aged <55 years at diagnosis) with very-low-risk prostate cancer (stage cT1c, with prostate-specific antigen [PSA] density of <0.15 ng/mL/g, Gleason score ≤6, and ≤2 positive biopsy cores with <50% tumour involvement) that may be candidates for active surveillance (AS).

PATIENTS AND METHODS

We queried a Department of Defense tumour registry and hard-copy records for servicemen diagnosed with prostate cancer from 1987 to 2010. Statistical analyses were undertaken using Fisher's exact and chi-square testing.

RESULTS

From 1987-1991 and 2007-2010, PSA screen-detected tumours diagnosed in men aged ≤55 years rose >30-fold. Data for a subset of men (174) with PSA screen-detected cancer were evaluable for disease risk assessment. Of the 174 men with screen-detected disease, 81 (47%) had very-low-risk disease. Of that group, 96% (78/81) selected treatment and, of 57 men undergoing radical prostatectomy (RP), the tumours of 49 (86%) carried favourable pathology (organ confined, <10% gland involvement, Gleason ≤6).

CONCLUSIONS

Nearly half of young men with PSA screen-detected prostate cancer are AS candidates but the overwhelming majority seek treatment. Considering that many tumours show favourable pathology at RP, there is a possibility that these patients may benefit from AS management.

Detection rate of clinically insignificant prostate cancer increases with repeat prostate biopsies

To analyze if clinically insignificant prostate cancer (CIPC) is more frequently detected with repeat prostate biopsies, we retrospectively analyzed the records of 2146 men diagnosed with prostate cancer after one or more prostate biopsies. The patients were divided into five groups according to the number of prostate biopsies obtained, e.g. group 1 had one biopsy, group 2 had two biopsies and group 3 had three biopsies. Of the 2146 patients diagnosed with prostate cancer, 1956 (91.1%), 142 (6.6%), 38 (1.8%), 9 (0.4%) and 1 (0.1%) men were in groups 1, 2, 3, 4 and 5, respectively. Groups 4 and 5 were excluded because of the small sample sizes. The remaining three groups (groups 1, 2 and 3) were statistically analyzed. There were no differences in age or prostate-specific antigen level among the three groups. CIPC was detected in 201 (10.3%), 28 (19.7%) and 9 (23.7%) patients in groups 1, 2 and 3, respectively (P<0.001). A multivariate analysis showed that the number of biopsies was an independent predictor to detect CIPC (OR=2.688 for group 2; OR=4.723 for group 3). In conclusion, patients undergoing multiple prostate biopsies are more likely to be diagnosed with CIPC than those who only undergo one biopsy. However, the risk still exists that the patient could have clinically significant prostate cancer. Therefore, when counseling patients with regard to serial repeat biopsies, the possibility of prostate cancer overdiagnosis and overtreatment must be balanced with the continued risk of clinically significant disease.

[Repeat prostate biopsies following a first negative biopsy in a context of an elevated prostate specific antigen]

INTRODUCTION

An elevated PSA and a negative prostate biopsy (PB) can be a false negative PB that ignores a prostate cancer (PCa) or a false positive PSA not related to PCa. The objective of this study was to analyze a group of patients who had a negative first BP for a PSA superior to 4 ng/mL and at least one additional PB and to compare these cases with controls who had the diagnosis PCa from the first PB.

METHODS

Retrospective single-center study comparing patients with an elevated PSA and repeat biopsy following a first negative PB and patients with PCa diagnosed from the first PB.

RESULTS

The 63 cases were younger than the 75 controls and had more often a normal digital rectal examination. Their prostate volume was larger and their number of PSA before the first PB lower: this corresponded to a lower PSA in the second (7/64), third (6/31), fourth (3/9) and sixth (1/1) PB. Among these cases with PCa, the length of core invaded by cancer and the total length of cancer of the entire PB were smaller than controls. In 76% of cases, the Gleason score among cases was 6 or less.

CONCLUSION

PCa discovered on repeat biopsy had features of better prognosis than those of controls. We propose an algorithm for management of patients with elevated PSA and negative first PB.

Differences in Postoperative Pathological Outcomes between Prostate Cancers Diagnosed at Initial and Repeat Biopsy

Purpose

We evaluated the differences in pathological outcomes between prostate cancers (PCas) diagnosed at initial and repeat biopsy.

Materials and Methods

We retrospectively reviewed the medical records of 287 patients who underwent radical retropubic prostatectomy from 2005 to 2010. We investigated preoperative factors, such as age, serum prostate-specific antigen (PSA), prostate volume (PV), digital rectal examination (DRE) results, biopsy schema, clinical stage, and number of prior biopsies, and postoperative pathological outcomes, including specimen volume, percent tumor volume, Gleason score (GS), tumor bilaterality, pathological stage, positive surgical margin (PSM), lymphovascular invasion (LVI), and perineural invasion (PNI). Patients were then classified into two groups by the number of prior biopsies (initial biopsy vs. repeat biopsy). We compared preoperative factors and postoperative pathological outcomes between the two groups.

Results

Of the 287 patients, 246 (85.7%) were diagnosed with cancer at the initial biopsy and 41 (14.3%) at the repeat biopsy. The repeat biopsy group was older (p=0.048), had a larger PV (p=0.009), had a significantly different biopsy schema (p<0.001), and had a lower (<10%) percentage tumor volume (p=0.016). In the multivariate analysis (after adjustment for biopsy schema, age, serum PSA, PV, and DRE), repeat biopsy was not an independent predictor of GS, tumor bilaterality, pathological stage, PSM, LVI, or PNI (p=0.212, 0.456, 0.459, 0.917, 0.991 and 0.827, respectively), but repeat biopsy could predict lower percentage tumor volume (p=0.037).

Conclusions

The pathological outcomes of PCas detected at repeat biopsy were not significantly different from those of PCas detected at initial biopsy except for a lower (<10%) percentage tumor volume.

Prospective assessment of prostate cancer aggressiveness using 3-T diffusion-weighted magnetic resonance imaging-guided biopsies versus a systematic 10-core transrectal ultrasound prostate biopsy cohort

BACKGROUND

Accurate pretreatment assessment of prostate cancer (PCa) aggressiveness is important in decision making. Gleason grade is a critical predictor of the aggressiveness of PCa. Transrectal ultrasound-guided biopsies (TRUSBxs) show substantial undergrading of Gleason grades found after radical prostatectomy (RP). Diffusion-weighted magnetic resonance imaging (MRI) has been shown to be a biomarker of tumour aggressiveness.

OBJECTIVE

To improve pretreatment assessment of PCa aggressiveness, this study prospectively evaluated MRI-guided prostate biopsies (MR-GBs) of abnormalities determined on diffusion-weighted imaging (DWI) apparent diffusion coefficient (ADC) maps. The results were compared with a 10-core TRUSBx cohort. RP findings served as the gold standard.

DESIGN, SETTING, AND PARTICIPANTS

A 10-core TRUSBx (n=64) or MR-GB (n=34) was used for PCa diagnosis before RP in 98 patients.

MEASUREMENTS

Using multiparametric 3-T MRI: T2-weighted, dynamic contrast-enhanced imaging, and DWI were performed to identify tumour-suspicious regions in patients with a negative TRUSBx. The regions with the highest restriction on ADC maps within the suspicions regions were used to direct MR-GB. A 10-core TRUSBx was used in a matched cohort. Following RP, the highest Gleason grades (HGGs) in biopsies and RP specimens were identified. Biopsy and RP Gleason grade results were evaluated using chi-square analysis.

RESULTS AND LIMITATIONS

No significant differences on RP were observed for proportions of patients having a HGG of 3 (35% vs 28%; p=0.50), 4 (32% vs 41%; p=0.51), and 5 (32% vs 31%; p=0.61) for the MR-GB and TRUSBx cohort, respectively. MR-GB showed an exact performance with RP for overall HGG: 88% (30 of 34); for TRUS-GB it was 55% (35 of 64; p=0.001). In the MR-GB cohort, an exact performance with HGG 3 was 100% (12 of 12); for HGG 4, 91% (10 of 11); and for HGG 5, 73% (8 of 11). The corresponding performance rates for TRUSBx were 94% (17 of 18; p=0.41), 46% (12 of 26; p=0.02), and 30% (6 of 20; p=0.01), respectively.

CONCLUSIONS

This study shows prospectively that DWI-directed MR-GBs significantly improve pretreatment risk stratification by obtaining biopsies that are representative of true Gleason grade.