Targeted Prostate Biopsy in the Era of Active Surveillance

Alternatives for MRI in Prostate Cancer Diagnostics-Review of Current Ultrasound-Based Techniques

The purpose of this review is to present the current role of ultrasound-based techniques in the diagnostic pathway of prostate cancer (PCa). With overdiagnosis and overtreatment of a clinically insignificant PCa over the past years, multiparametric magnetic resonance imaging (mpMRI) started to be recommended for every patient suspected of PCa before performing a biopsy. It enabled targeted sampling of the suspicious prostate regions, improving the accuracy of the traditional systematic biopsy. However, mpMRI is associated with high costs, relatively low availability, long and separate procedure, or exposure to the contrast agent. The novel ultrasound modalities, such as shear wave elastography (SWE), contrast-enhanced ultrasound (CEUS), or high frequency micro-ultrasound (MicroUS), may be capable of maintaining the performance of mpMRI without its limitations. Moreover, the real-time lesion visualization during biopsy would significantly simplify the diagnostic process. Another value of these new techniques is the ability to enhance the performance of mpMRI by creating the image fusion of multiple modalities. Such models might be further analyzed by artificial intelligence to mark the regions of interest for investigators and help to decide about the biopsy indications. The dynamic development and promising results of new ultrasound-based techniques should encourage researchers to thoroughly study their utilization in prostate imaging.

Diagnostic Yield of Incremental Biopsy Cores and Second Lesion Sampling for In-Gantry MRI-Guided Prostate Biopsy

BACKGROUND. In-gantry MRI-guided biopsy (MRGB) of the prostate has been shown to be more accurate than other targeted prostate biopsy methods. However, the optimal number of cores to obtain during in-gantry MRGB remains undetermined. OBJECTIVE. The purpose of this study was to assess the diagnostic yield of obtaining an incremental number of cores from the primary lesion and of second lesion sampling during in-gantry MRGB of the prostate. METHODS. This retrospective study included 128 men with 163 prostate lesions who underwent in-gantry MRGB between 2016 and 2019. The men had a total of 163 lesions sampled with two or more cores, 121 lesions sampled with three or more cores, and 52 lesions sampled with four or more cores. A total of 40 men underwent sampling of a second lesion. Upgrade on a given core was defined as a greater International Society of Urological Pathology (ISUP) grade group (GG) relative to the previously obtained cores. Clinically significant prostate cancer (csPCa) was defined as ISUP GG 2 or greater. RESULTS. The frequency of any upgrade was 12.9% (21/163) on core 2 versus 10.7% (13/121) on core 3 (p = .29 relative to core 2) and 1.9% (1/52) on core 4 (p = .03 relative to core 3). The frequency of upgrade to csPCa was 7.4% (12/163) on core 2 versus 4.1% (5/121) on core 3 (p = .13 relative to core 2) and 0% (0/52) on core 4 (p = .07 relative to core 3). The frequency of upgrade on core 2 was higher for anterior lesions (p < .001) and lesions with a higher PI-RADS score (p = .007); the frequency of upgrade on core 3 was higher for apical lesions (p = .01) and lesions with a higher PI-RADS score (p = .01). Sampling of a second lesion resulted in an upgrade in a single patient (2.5%; 1/40); both lesions were PI-RADS category 4 and showed csPCa. CONCLUSION. When performing in-gantry MRGB of the prostate, obtaining three cores from the primary lesion is warranted to optimize csPCa diagnosis. Obtaining a fourth core from the primary lesion or sampling a second lesion has very low yield in upgrading cancer diagnoses. CLINICAL IMPACT. To reduce patient discomfort and procedure times, operators may refrain from obtaining more than three cores or second lesion sampling.

Indication for Active Surveillance in the Era of MRI-Targeted Prostate Biopsies

INTRODUCTION

Active surveillance (AS) strategies were established to avoid overtreatment of low-risk prostate cancer (PCa) patients. Low tumor volume represents one indication criteria; however, applying this criterion after MRI-targeted prostate biopsies may lead to overestimation of tumor volume; wherefore, patients suitable for AS would be exposed to the risk of overtreatment.

METHODS

This retrospective analysis included 318 patients in which PCa was detected by MRI-TRUS fusion prostate biopsy. Classic and extended indication for AS included Gleason 6 and Gleason 3 + 4 cancer, respectively. We assessed the effect of targeted biopsies and temporary rating strategies on eligibility for AS and developed new "composite" algorithms to more accurately assess eligibility for AS.

RESULTS

Forty-four (13.8%) and 60 (18.9%) of the 318 patients qualified for AS according to "classic" and "extended" criteria, respectively. Application of the "composite 1" definition led to AS eligibility of 52 of 248 patients (20.97%) in the classic and of 77 of 248 patients (31.05%) in the "extended" group.

CONCLUSIONS

We could demonstrate that classic algorithms led to ineligibility of patients for AS. We propose a new rating algorithm to improve tumor assessment for a more accurate indication for AS.

MRI/US fusion prostate biopsy in men on active surveillance: Our experience

AIM

The upgrading or staging in men with prostate cancer (PCA) undergoing active surveillance (AS), defined as Gleason score (GS) ≥ 3+4 or more than 2 area with cancer, was investigated in our experience using the software-based fusion biopsy (FB).

METHODS

We selected from our database, composed of 620 biopsies, only men on AS according to criteria of John Hopkins Protocol (T1c, < 3 positive cores, GS = 3+3 = 6). Monitoring consisted of PSA measurement every 3 months, a clinical examination every 6 months, confirmatory FB within 6 months and then annual FB in all men. The suspicious MRI lesions were scored according to the Prostate Imaging Reporting and Data System (PI-RADS) classification version 2. FB were performed with a transrectal elastic free-hand fusion platform. The overall and clinically significant cancer detection rate was reported. Secondary, the diagnostic role of systematic biopsies was evaluated.

RESULTS

We selected 56 patients on AS with mean age 67.4 years, mean PSA 6.7 ng/ml and at least one follow-up MRI-US fusion biopsy (10 had 2 or 3 follow-up biopsies). Lesions detected by MRI were: PIRADS-2 in 5, PIRADS-3 in 28, PIRADS-4 in 18 pts and PIRADS-5 in 5 patients. In each MRI lesion, FB with 2.1 ± 1.1 cores were taken with a mean total cores of 13 ± 2.4 including the systematic cores. The overall cancer detection rate was 71% (40/56): 62% (25/40) in target core and 28% (15/40) in systematic core. The overall significant cancer detection rate was 46% (26/56): 69% (18/26) in target vs 31% (8/26) in random cores.

CONCLUSIONS

The incidence of clinical significant cancer was 46% in men starting active surveillance, but it was more than doubled using MRI/US Target Biopsy 69% (18/26) rather than random cores (31%, 8/26). However, 1/3 of disease upgrades would have been missed if only the targeted biopsies were performed. Based on our experience, MRI/US fusion target biopsy must be associated to systematic biopsies to improve detection of significant cancer, reducing the risks of misclassification.

Prognostic capabilities and clinical utility of cell cycle progression testing, prostate imaging reporting and data system, version 2, and clinicopathologic data in management of localized prostate cancer

OBJECTIVES

To compare the prognostic capabilities and clinical utility of the cell cycle progression (CCP) gene expression classifier test, multiparametric magnetic resonance imaging (mpMRI) with Prostate Imaging Reporting and Data System (PI-RADS) scoring, and clinicopathologic data in select prostate cancer (PCa) medical management scenarios.

PATIENTS AND METHODS

Retrospective, observational analysis of patients (N = 222) ascertained sequentially from a single urology practice from January 2015 to June 2018. Men were included if they had localized PCa, a CCP score, and an mpMRI PI-RADS v2 score. Cohort 1 (n = 156): men with newly diagnosed PCa, with or without a previous negative biopsy. Cohort 2 (n = 66): men who initiated active surveillance (AS) without CCP testing, but who received the test during AS. CCP was combined with the UCSF Cancer of the Prostate Risk Assessment (CAPRA) score to produce a clinical cell-cycle risk (CCR) score, which was reported in the context of a validated AS threshold. Spearman's rank correlation test was used to evaluate correlations between variables. Generalized linear models were used to predict binary Gleason score category and medical management selection (AS or curative therapy). Likelihood-ratio tests were used to determine predictor significance in both univariable and multivariable models.

RESULTS

In the combined cohorts, modest but significant correlations were observed between PI-RADS score and CCP (r_s = 0.22, P = 8.1 × 10^-4), CAPRA (r_s= 0.36, P = 4.8 × 10^-8), or CCR (r_s = 0.37, P = 2.0 × 10^-8), suggesting that much of the prognostic information captured by these measures is independent. When accounting for CAPRA and PI-RADS score, CCP was a significant predictor of higher-grade tumor after radical prostatectomy, with the resected tumor approximately 4 times more likely to harbor Gleason ≥4+3 per 1-unit increase in CCP in Cohort 1 (Odds Ratio [OR], 4.10 [95% confidence interval [CI], 1.46, 14.12], P = 0.006) and in the combined cohorts (OR, 3.72 [95% CI, 1.39, 11.88], P = 0.008). On multivariable analysis, PI-RADS score was not a significant predictor of post-radical prostatectomy Gleason score. Both CCP and CCR were significant and independent predictors of AS versus curative therapy in Cohort 1 on multivariable analysis, with each 1-unit increase in score corresponding to an approximately 2-fold greater likelihood of selecting curative therapy (CCP OR, 2.08 [95% CI, 1.16, 3.94], P = 0.014) (CCR OR, 2.33 [95% CI, 1.48, 3.87], P = 1.5 × 10^-4). CCR at or below the AS threshold significantly reduced the probability of selecting curative therapy over AS (OR, 0.28 [95% CI, 0.13, 0.57], P = 4.4 × 10^-4), further validating the clinical utility of the AS threshold.

CONCLUSION

CCP was a better predictor of both tumor grade and subsequent patient management than was PI-RADS. Even in the context of targeted biopsy, molecular information remains essential to ensure precise risk assessment for men with newly diagnosed PCa.

Role of Multiparametric Prostate Magnetic Resonance Imaging before Confirmatory Biopsy in Assessing the Risk of Prostate Cancer Progression during Active Surveillance

Objective

To evaluate the impact of multiparametric magnetic resonance imaging (mpMRI) before confirmatory prostate biopsy in patients under active surveillance (AS).

Materials and Methods

This retrospective study included 170 patients with Gleason grade 6 prostate cancer initially enrolled in an AS program between 2011 and 2019. Prostate mpMRI was performed using a 1.5 tesla (T) magnetic resonance imaging system with a 16-channel phased-array body coil. The protocol included T1-weighted, T2-weighted, diffusion-weighted, and dynamic contrast-enhanced imaging sequences. Uroradiology reports generated by a specialist were based on prostate imaging-reporting and data system (PI-RADS) version 2. Univariate and multivariate analyses were performed based on regression models.

Results

The reclassification rate at confirmatory biopsy was higher in patients with suspicious lesions on mpMRI (PI-RADS score ≥ 3) (n = 47) than in patients with non-suspicious mpMRIs (n = 61) and who did not undergo mpMRIs (n = 62) (66%, 26.2%, and 24.2%, respectively; p < 0.001). On multivariate analysis, presence of a suspicious mpMRI finding (PI-RADS score ≥ 3) was associated (adjusted odds ratio: 4.72) with the risk of reclassification at confirmatory biopsy after adjusting for the main variables (age, prostate-specific antigen density, number of positive cores, number of previous biopsies, and clinical stage). Presence of a suspicious mpMRI finding (adjusted hazard ratio: 2.62) was also associated with the risk of progression to active treatment during the follow-up.

Conclusion

Inclusion of mpMRI before the confirmatory biopsy is useful to stratify the risk of reclassification during the biopsy as well as to evaluate the risk of progression to active treatment during follow-up.

Proteomic Tissue-Based Classifier for Early Prediction of Prostate Cancer Progression

Although ~40% of screen-detected prostate cancers (PCa) are indolent, advanced-stage PCa is a lethal disease with 5-year survival rates around 29%. Identification of biomarkers for early detection of aggressive disease is a key challenge. Starting with 52 candidate biomarkers, selected from existing PCa genomics datasets and known PCa driver genes, we used targeted mass spectrometry to quantify proteins that significantly differed in primary tumors from PCa patients treated with radical prostatectomy (RP) across three study outcomes: (i) metastasis ≥1-year post-RP, (ii) biochemical recurrence ≥1-year post-RP, and (iii) no progression after ≥10 years post-RP. Sixteen proteins that differed significantly in an initial set of 105 samples were evaluated in the entire cohort (n = 338). A five-protein classifier which combined FOLH1, KLK3, TGFB1, SPARC, and CAMKK2 with existing clinical and pathological standard of care variables demonstrated significant improvement in predicting distant metastasis, achieving an area under the receiver-operating characteristic curve of 0.92 (0.86, 0.99, p = 0.001) and a negative predictive value of 92% in the training/testing analysis. This classifier has the potential to stratify patients based on risk of aggressive, metastatic PCa that will require early intervention compared to low risk patients who could be managed through active surveillance.

Multiparametric magnetic resonance imaging ultrasound-guided fusion biopsy during active surveillance: A single-centre study

Objective

To analyse the role of multiparametric magnetic resonance imaging (mpMRI) ultrasound (US)-guided fusion biopsy (FB) in patients with low-risk prostate cancer (PCa) under active surveillance (AS).

Patients and methods

Our retrospective study included 47 patients under AS who consecutively underwent both FB and standard biopsy (SB), from May 2015 until November 2017. We defined FB as a transrectal US-guided biopsy based on mpMRI. The primary endpoint was to assess the rate of concordance between FB and SB in terms of diagnostic yield, as well as the rate of Gleason Score upgrading/downgrading between the two techniques. Cohen’s kappa coefficient (κ) was applied to test the concordance between FB and SB.

Results

The median (interquartile range [IQR]) follow-up was 20 (13–37) months. The median (IQR) number of cores taken was 13 (12–14) at SB and 4 (4–6) at FB. Overall, FB missed 12/47 (26%) PCa diagnoses compared to SB. There was concordance between SB and FB in 64% of the patients. The κ showed a perfect agreement between SB and FB for the detection of PCa with Gleason Score 4 + 4 and a weak concordance for negative biopsies (κ: 0.46) and for PCa with a Gleason Score 4 + 3 (κ: 0.54). There was Gleason Score upgrading at FB in two of 47 (4%) patients, whereas there was downgrading in three of 47 (6%) patients.

Conclusion

In our present study, FB showed no superiority over SB for the detection of PCa. On the contrary, FB had a high rate of missed PCa compared to SB. Further studies are required to ascertain the role of FB in AS.

Abbreviations

AS: active surveillance; FB: fusion biopsy; IL: index lesion; IQR: interquartile range; mpMRI: multiparametric MRI; (cs)PCa: (clinically significant) prostate cancer; PI-RADS: Prostate Imaging-Reporting and Data System; PRIAS: Prostate Cancer Research International Active Surveillance; ROI: region of interest; SB: standard biopsy

Impact of MRI and Targeted Biopsies on Eligibility and Disease Reclassification in MRI-positive Candidates for Active Surveillance on Systematic Biopsies

OBJECTIVE

To assess the impact of concomitant targeted biopsies (TB) for predicting final disease reclassification in MRI-positive low-risk prostate cancer patients eligible for active surveillance (AS) on systematic biopsies (SB).

MATERIALS AND METHODS

From a prospective database, we included all prebiopsy MRI-positive men fulfilling AS criteria at diagnosis (Toronto [n = 114], UCSF [n = 82], or PRIAS [n = 60] criteria) on SB. All patients underwent a combination of SB and software-based fusion TB, and an immediate radical prostatectomy. The primary endpoints were the pathologic upgrading and upstaging rates.

RESULTS

Biopsy grade group was upgraded to grade group (GG) 2 and to GG≥3 on TB in 65.9%-76.7% and in 12.2-16.7%, respectively. The rate of GG ≥3 in radical prostatectomy specimens varied from 31.6% to 43.3% with no relation between strictest criteria and lower upgrading rates. The proportion of not organ-confined disease (35%-39%) was comparable among the AS cohorts. Negative TB was strongly associated with the absence of final GG ≥3. Tumor grade on TB was significantly correlated with the risk of final GG ≥3 in both Toronto and UCSF cohorts, not in the PRIAS cohort. In the PRIAS cohort, the only independent predictive factor for GG ≥3 disease was the maximal tumor length in any core (P = .034).

CONCLUSION

In MRI-positive patients, the risk of disease reclassification was comparable whatever the SB-based AS criteria used. TB were predictive of final upgrading, with a varied impact according to the AS criteria. SB features remained relevant for reclassification prediction even in case of positive TB. The risk of upstaged disease remains important, approximately one third, and neither TB/SB parameters nor MRI findings could accurately predict it.

Magnetic Resonance Imaging-Guided Confirmatory Biopsy for Initiating Active Surveillance of Prostate Cancer

Importance

Transrectal, ultrasonography-guided prostate biopsy often fails to disclose the severity of underlying pathologic findings for prostate cancer. Magnetic resonance imaging (MRI)-guided biopsy may improve the characterization of prostate pathologic results, but few studies have examined its use for the decision to enter active surveillance.

Objective

To evaluate whether confirmatory biopsy findings by MRI guidance are associated with the risk of pathologic disease upgrading among patients with prostate cancer during active surveillance.

Design, Settings, and Participants

This retrospective cohort study used prospectively obtained registry data from 332 men with prostate cancer of Gleason grade group (GG) 2 or lower who were referred for active surveillance at a large academic medical center from January 1, 2009, through December 31, 2017.

Exposures

All confirmatory and follow-up biopsies were performed using MRI guidance with an MRI-ultrasonography fusion device. Patients underwent repeated MRI-guided biopsies every 12 to 24 months. At follow-up sessions, in addition to obtaining systematic samples, lesions seen on MRI were targeted and foci of low-grade prostate cancer were obtained again using tracking technology. Active surveillance was terminated with detection of at least GG3 disease or receipt of treatment.

Main Outcomes and Measures

The primary outcome was upgrading to at least GG3 disease during active surveillance. Secondary outcomes were the associations of MRI lesion grade, prostate-specific antigen (PSA) level, PSA density, and biopsy method (targeted, systematic, or tracked) with the primary outcome.

Results

Of 332 patients (mean [SD] age, 62.8 [7.6] years), 39 (11.7%) upgraded to at least GG3 disease during follow-up. The incidence of upgrading was 7.9% (9 of 114) when the confirmatory biopsy finding was normal, 11.4% (20 of 175) when the finding showed GG1 disease, and 23.3% (10 of 43) when the finding was GG2 disease (P = .03). Men with GG2 disease were almost 8 times more likely to upgrade during surveillance compared with those with normal findings but only among those with low PSA density (hazard ratio [HR], 7.82; 95% CI, 2.29-26.68). A PSA density of at least 0.15 ng/mL/mL was associated with increased risk of upgrading among patients with normal findings (HR, 7.21; 95% CI, 1.98-26.24) or GG1 disease (HR, 2.86; 95% CI, 1.16 to 7.03) on confirmatory biopsy. A total of 46% of pathologic disease upgrades would have been missed if only the targeted biopsy was performed and 65% of disease upgrades were detected only with tracked biopsy.

Conclusions and Relevance

The findings suggest that confirmatory biopsy with MRI guidance is significantly associated with future disease upgrading of prostate cancer, especially when combined with PSA density, and should be considered as an appropriate entry point for active surveillance. Systematic and targeted biopsies were additive in detection of clinically significant cancers. Repeated biopsy at sites at which findings were previously abnormal (tracking biopsy) facilitated detection of cancers not suitable for continued active surveillance.

The use of prostate MR for targeting prostate biopsies

Management of prostate cancer relies heavily on accurate risk stratification obtained through biopsies, which are conventionally performed under transrectal ultrasound (TRUS) guidance. Yet, multiparametric MRI has grown to become an integral part of the care of males with known or suspected prostate cancer. This article will discuss in detail the different MRI-targeted biopsy techniques, their advantages and disadvantages, and the impact they have on patient management.

Performance of systematic, MRI-targeted biopsies alone or in combination for the prediction of unfavourable disease in MRI-positive low-risk prostate cancer patients eligible for active surveillance

PURPOSE

To assess the upstaging/upgrading rates of low-risk prostate cancer (PCa) according to the biopsy scheme used (systematic (SB), targeted biopsies (TB), or both) in the setting of positive pre-biopsy MRI.

PATIENTS AND METHODS

We included 143 consecutive men fulfilling the Toronto University active surveillance (AS) criteria who underwent a pre-biopsy positive MRI, a combination of SB and software-based fusion TB, and a radical prostatectomy, in two expert centres. The primary endpoints were the pathological upgrading and upstaging rates. Overall unfavourable disease (OUD) was defined by any pT3-4 and/or pN1 and/or ≥ GG 3.

RESULTS

Using TB alone would have missed 21.7% of cancers including 16.7% of ≥ GG 3. The use of TB was significantly associated with a lower risk of ≥ Grade Group (GG) 3 disease (p < 0.006) in RP specimens. Combination of SB and TB lowered this risk by 39%, compared with TB alone. The biopsy scheme did not affect the upstaging rates which were substantial even in case of combination scheme (from 37 to 46%). OUD was detected in approximately 50% of cases. The presence of high grade on TB was the only independent predictive factor for both ≥ GG 2 (p = 0.015) and ≥ GG 3 (p = 0.023) in RP specimens.

CONCLUSIONS

High grade on TB biopsies represented the major predictor of upgrading. Combination of SB and TB better defined the sub-group of patients having the lowest risk of reclassification, compared with TB or SB alone. The risk of non-organ-confined disease remained high, and could not be accurately predicted by MRI or systematic/targeted biopsy features.

Association of training level and outcome of software-based image fusion-guided targeted prostate biopsies

PURPOSE

The aim of this study was to assess the impact of experience on the outcome of image fusion-guided prostate biopsies performed by urologists working at a high-volume medical center.

METHODS

The first 210 consecutive fusion biopsies were analyzed following installation of the software-based biopsy platform Artemis™ (Eigen, USA). The impact of training was measured in terms of changes in prostate cancer detection rates and biopsy duration over time. We sought to identify a threshold of experience for urologists, which predicts higher detection rates of targeted biopsies. The influence of various factors on prostate cancer detection rates was evaluated using bi- and multivariate analysis.

RESULTS

Twenty-two urologists (n = 9 senior urologists, n = 13 urological residents) performed targeted biopsies followed by systematic 12-core biopsies. Overall, targeted biopsies yielded a positive result in 39.6% of 260 suspicious MRI lesions. A subgroup analysis of the six urologists who performed more than ten biopsies was then conducted, and their level of experience (i.e., performance of more than eight biopsies) was found to be associated with higher detection rates than those with less experience (49.0% and 23.0%, respectively; p < 0.001) in the targeted biopsies. Experience was likewise a significant and independent predictor of a cancer-positive targeted biopsy (p = 0.002). Experienced senior physicians did not outperform residents in their targeted biopsy results. Further, biopsy duration correlated negatively (r = - 0.5931, p < 0.001) with the total number of biopsies performed for all subgroups during the period of assessment.

CONCLUSIONS

Experience is an important predictor of the rate of detection in targeted biopsies using software-based biopsy platforms with semi-robotic assistance. Moreover, the performance of just a few procedures appears sufficient to increase biopsy effectiveness significantly. Lastly, supervision by experts is recommended during the training phase.

Active Surveillance Magnetic Resonance Imaging Study (ASIST): Results of a Randomized Multicenter Prospective Trial

BACKGROUND AND OBJECTIVE

This study aimed to determine, in men recently diagnosed with grade group 1 (GG1) prostate cancer, if magnetic resonance imaging (MRI) with targeted biopsy could identify a greater proportion of men with GG ≥2 cancer on their confirmatory biopsy compared with systematic biopsies. The study was registered with www.clinicaltrials.gov (NCT01354171).

DESIGN, SETTING, AND PARTICIPANTS

This study is a prospective, randomized, multicenter, open-label trial. Eligible patients were men diagnosed with GG1 cancer within 1 yr prior to study entry in whom a confirmatory biopsy was indicated. Patients were randomized to 12-core systematic biopsy or MRI with systematic and targeted biopsy using the Artemis fusion targeting system. The primary end point was the proportion upgraded to GG ≥2 in each arm.

RESULTS AND LIMITATIONS

In total, 296 men were registered and 273 randomized. Of the MRI group, 64% had a region of interest. No difference was observed in the rate of GG ≥2 upgrading (the intent-to-treat population, p=0.7, and per-protocol [PP] population, p=0.4), GG ≥2 upgrading within each stratum separately, or GG ≥3. After central pathology review, upgrading was observed in 36/132 (27%) men in the systematic biopsy arm and 42/127 (33%) men in the MRI arm (p=0.3). Upgrading was seen in 19/137 (14%) patients in the MRI arm on targeted biopsy alone (median, 2 cores) compared with 31/136 (23%) in the systematic biopsy arm (median, 12 cores; p=0.09). In the MRI arm, 8/127 (6.5%) patients had GG ≥2 disease identified on targeted biopsy, but ≤GG1 on the systematic biopsy, and 10/127 (7.9%) patients had GG ≥2 disease identified by systematic biopsy but ≤GG1 on targeted biopsy. Significant differences in upgrading on targeted biopsies were seen between sites, likely reflecting different levels of expertise with the targeted biopsy technique.

CONCLUSIONS

The addition of MRI with targeted biopsies to systematic biopsies did not significantly increase the upgrading rate compared with systematic biopsy alone. Furthermore, 2-core targeted biopsies alone resulted in a nonsignificant trend to less upgrading than 12-core systematic biopsy (p=0.09). In men on active surveillance, targeted biopsies identify most, but not all, clinically significant cancers.

MR-guided biopsy and focal therapy: new options for prostate cancer management

PURPOSE OF REVIEW

Options for prostate cancer management are rapidly expanding. The recent advent of MRI technology has led to guided prostate biopsies by radiologists working in-bore or by urologists using MR/US fusion technology. The resulting tumor visualization now provides the option of focal therapy. Currently available are highly directed energies - focused ultrasound (HIFU), cryotherapy, and laser - all offering the hope of curing prostate cancer with few side effects.

RECENT FINDINGS

MRI now enables visualization of many prostate cancers. MR/US fusion biopsy makes possible the targeted biopsy of suspicious lesions efficiently in the urology clinic. Several fusion devices are now commercially available. Focal therapy, a derivative of targeted biopsy, is reshaping the approach to treatment of some prostate cancers. Focal laser ablation, originally done in the MRI gantry (in-bore), promises to soon become feasible in a clinic setting (out-of-bore) under local anesthesia. Other focal therapy options, including HIFU and cryotherapy, are currently available. Herein are summarized outcomes data on focal therapy modalities.

SUMMARY

MRI-guided biopsy is optimizing prostate cancer diagnosis. Focal therapy, an outgrowth of guided biopsy, promises to become a well tolerated and effective approach to treating many men with prostate cancer while minimizing the risks of incontinence and impotence from radical treatment.