Value of Tracking Biopsy in Men Undergoing Active Surveillance of Prostate Cancer

Cost-Effectiveness of Annual Prostate MRI and Potential MRI-Guided Biopsy After Prostate-Specific Antigen Test Results

Importance

Magnetic resonance imaging (MRI) and potential MRI-guided biopsy enable enhanced identification of clinically significant prostate cancer. Despite proven efficacy, MRI and potential MRI-guided biopsy remain costly, and there is limited evidence regarding the cost-effectiveness of this approach in general and for different prostate-specific antigen (PSA) strata.

Objective

To examine the cost-effectiveness of integrating annual MRI and potential MRI-guided biopsy as part of clinical decision-making for men after being screened for prostate cancer compared with standard biopsy.

Design, Setting, and Participants

Using a decision analytic Markov cohort model, an economic evaluation was conducted projecting outcomes over 10 years for a hypothetical cohort of 65-year-old men in the US with 4 different PSA strata (<2.5 ng/mL, 2.5-4.0 ng/mL, 4.1-10.0 ng/mL, >10 ng/mL) identified by screening through Monte Carlo microsimulation with 10 000 trials. Model inputs for probabilities, costs in 2020 US dollars, and quality-adjusted life-years (QALYs) were from the literature and expert consultation. The model was specifically designed to reflect the US health care system, adopting a federal payer perspective (ie, Medicare).

Exposures

Magnetic resonance imaging with potential MRI-guided biopsy and standard biopsy.

Main Outcomes and Measures

Incremental cost-effectiveness ratios (ICERs) using a willingness-to-pay threshold of $100 000 per QALY was estimated. One-way and probabilistic sensitivity analyses were performed.

Results

For the 3 PSA strata of 2.5 ng/mL or greater, the MRI and potential MRI-guided biopsy strategy was cost-effective compared with standard biopsy (PSA 2.5-4.0 ng/mL: base-case ICER, $21 131/QALY; PSA 4.1-10.0 ng/mL: base-case ICER, $12 336/QALY; PSA >10.0 ng/mL: base-case ICER, $6000/QALY). Results varied depending on the diagnostic accuracy of MRI and potential MRI-guided biopsy. Results of probabilistic sensitivity analyses showed that the MRI and potential MRI-guided biopsy strategy was cost-effective at the willingness-to-pay threshold of $100 000 per QALY in a range between 76% and 81% of simulations for each of the 3 PSA strata of 2.5 ng/mL or more.

Conclusions and Relevance

This economic evaluation of a hypothetical cohort suggests that an annual MRI and potential MRI-guided biopsy was a cost-effective option from a US federal payer perspective compared with standard biopsy for newly eligible male Medicare beneficiaries with a serum PSA level of 2.5 ng/mL or more.

Possible clinical implications of prostate capsule thickness and glandular epithelial cell density in benign prostate hyperplasia

PURPOSE

The negative correlation between BPH-size and incidence of prostate cancer (PCa) is well-documented in the literature, however the exact mechanism is not well-understood. The present study uses histo-anatomical imaging to study prostate volume in correlation to prostate capsule thickness, and glandular epithelial cell density within the peripheral zone (PZ).

MATERIALS AND METHODS

Specimens were selected from radical prostatectomies ranging from 20 to 160 mL based on ease of anatomical reconstruction by the slides. A total of 60 patients were selected and underwent quantitative measurements of prostate capsule thickness and glandular epithelial density within the PZ using computer-based imaging software. Pearson's correlation and a stepwise multiple linear regression analysis was conducted to determine the relationship between these measured parameters and the clinical characteristic of these patients.

RESULTS

Pearson's correlation analysis revealed a strongly significant, negative correlation between prostate volume and glandular epithelial cell density (r(58)=-0.554, p<0.001), and a strongly significant, positive correlation between prostate volume and average capsule thickness (r(58)=0.462, p<0.001). Results of multiple regression analysis showed that average glandular epithelial cell density added statistically to this prediction (p<0.05).

CONCLUSIONS

The results suggest that growth of the transition zone in BPH causes increased fibrosis of the PZ, leading to atrophy and fibrosis of glandular cells. As 80% of PCa originates from the glandular epithelium within the PZ, this observed phenomenon may explain the inverse correlation between BPH and PCa that is well-documented in the literature.

Comparison of Targeted vs Systematic Prostate Biopsy in Men Who Are Biopsy Naive: The Prospective Assessment of Image Registration in the Diagnosis of Prostate Cancer (PAIREDCAP) Study

Importance

Magnetic resonance imaging (MRI) guidance improves the accuracy of prostate biopsy for the detection of clinically significant prostate cancer, but the optimal use of such guidance is not yet clear.

Objective

To determine the cancer detection rate (CDR) of targeting MRI-visible lesions vs systematic prostate sampling in the diagnosis of clinically significant prostate cancer in men who were biopsy naive.

Design, Setting, and Participants

This paired cohort trial, known as the Prospective Assessment of Image Registration in the Diagnosis of Prostate Cancer (PAIREDCAP) study, was conducted in an academic medical center from January 2015 to April 2018. Men undergoing first-time prostate biopsy were enrolled. Paired-cohort participants were a consecutive series of men with MRI-visible lesions (defined by a Prostate Imaging Reporting & Data System version 2 score  ≥ 3), who each underwent 3 biopsy methods at the same sitting: first, a systematic biopsy; second, an MRI-lesion biopsy targeted by cognitive fusion; and third, an MRI-lesion targeted by software fusion. Another consecutive series of men without MRI-visible lesions underwent systematic biopsies to help determine the false-negative rate of MRI during the trial period.

Main Outcomes and Measures

The primary end point was the detection rate of clinically significant prostate cancer (Gleason grade group ≥2) overall and by each biopsy method separately. The secondary end points were the effects of the Prostate Imaging Reporting & Data System version 2 grade, prostate-specific antigen density, and prostate volume on the primary end point. Tertiary end points were the false-negative rate of MRI and concordance of biopsy-method results by location of detected cancers within the prostate.

Results

A total of 300 men participated; 248 had MRI-visible lesions (mean [SD] age, 65.5 [7.7] years; 197 were white [79.4%]), and 52 were control participants (mean [SD] age, 63.6 [5.9] years; 39 were white [75%]). The overall CDR was 70% in the paired cohort group, achieved by combining systematic and targeted biopsy results. The CDR by systematic sampling was 15% in the group without MRI-visible lesions. In the paired-cohort group, CDRs varied from 47% (116 of 248 men) when using cognitive fusion biopsy alone, to approximately 60% when using systematic biopsy (149 of 248 men) or either fusion method alone (154 of 248 men), to 70% (174 of 248 men) when combining systematic and targeted biopsy. Discordance of tumor locations suggests that the different biopsy methods detect different tumors. Thus, combining targeting and systematic sampling provide greatest sensitivity for detection of clinically significant prostate cancer. For all biopsy methods, the Prostate Imaging Reporting & Data System version 2 grade and prostate-specific antigen density were directly associated with CDRs, and prostate volume was inversely associated.

Conclusions and Relevance

An MRI-visible lesion in men undergoing first-time prostate biopsy identifies those with a heightened risk of clinically significant prostate cancer. Combining targeted and systematic biopsy offers the best chances of detecting the cancer.

Development and External Validation of Multiparametric MRI-Derived Nomogram to Predict Risk of Pathologic Upgrade in Patients on Active Surveillance for Prostate Cancer

OBJECTIVE. The aim of this study was to create, develop, and externally validate a nomogram that predicts pathologic upgrade in patients on active surveillance (AS) for prostate cancer using commonly available clinical and multiparametric MRI (mpMRI) factors. MATERIALS AND METHODS. A consecutive sample of 300 patients undergoing AS for prostate cancer at the Keimyung University Dongsan Hospital between 2010 and 2016 was used to develop the nomogram. The validation cohort consisted of 150 patients undergoing active surveillance at Kyungpook National University Hospital between 2013 and 2017. The study outcome was the occurrence of pathologic upgrade in AS patients. The relationship between the clinical and mpMRI factors considered and pathologic upgrade was tested using univariate and multivariate logistic regression analyses. The predictive accuracy of the nomogram was determined using the ROC AUC. RESULTS. The overall rate of pathologic upgrade was 25.0% in the developmental cohort and 22.0% in the validation cohort. Significant variables in the models were age, prostate-specific antigen level, biopsy grade group 2, baseline Prostate Imaging Reporting and Data System (PI-RADS) scores of 4 and 5, positive cores on initial biopsy greater than 1, and biopsy cores with 50% or more tumor involvement. The progression seen on mpMRI of PI-RADS score was significantly associated with pathologic upgrade. The nomogram used to predict the risk of pathologic upgrade had a predictive accuracy of 0.78 in the external validation cohort. CONCLUSION. This study developed and externally validated a nomogram that predicts the risk of pathologic upgrade on the basis of commonly used factors. This nomogram may be used to assist management decision making for patients on AS for prostate cancer.

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.

Prostate biopsy: guidelines and evidence

PURPOSE OF REVIEW

To summarize the highest level evidence that was acquired within the last years, with regard to diagnosis of prostate cancer. With many secondary diagnostic tools becoming available, and not being mentioned in the guidelines, this review is meant to assist clinical decision-making in initial biopsy and rebiopsy settings.

RECENT FINDINGS

The PROMIS Trial delivered level 1b evidence about the diagnostic accuracy of prostate multiparametric MRI (mpMRI) as a triage tool for prostate biopsy. MRI-ultrasound-fusions-targeted biopsy has been evaluated and compared with the standard of care, and has been found to have a higher cancer detection rate. The different approaches to MRI-guided biopsies do not show significant differences. Urine biomarkers analysing RNA as well as genetic assays of biopsy specimen have also shown to be helpful in the decision to (re-)biopsy a patient, especially in combination with MRI.

SUMMARY

Patients and doctors alike have been trying to avoid prostate biopsies, the risks, and the side effects of potential overtreatment. Imaging and other biomarkers are used to increase diagnostic accuracy, yielding more precise information to act on. None of these secondary diagnostic tools are perfect, yet they can, and should be used if one stays aware of their limitations.

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.

Use of MRI-Guided Biopsy for Selection and Follow-up of Men Undergoing Hemi-gland Cryoablation of Prostate Cancer

OBJECTIVE

To investigate safety, efficacy, and quality of life impact of hemi-gland cryotherapy for clinically-significant prostate cancer (CaP), when patient selection and follow-up includes MRI-guided biopsy.

METHODS

Twenty-nine men with unilateral CaP (all clinically significant with prostate volume <60 cc) were enrolled in a prospective observational trial of hemi-gland cryotherapy. Mean patient age was 68.7 years. Median prostate-specific antigen (PSA) was 6.6 ng/mL. MRI-guided biopsy (3T-MRI, Artemis US fusion) was used for diagnosis and repeated at 6-month follow-up in all men. Treatment was under general anesthesia using the BTG/Galil system. Validated questionnaires were used to determine effects of treatment on urinary and sexual function and quality of life.

RESULTS

Cryotherapy was completed satisfactorily in all 29 cases in <60 minutes with no intraoperative complications. Significant decreases in PSA (median decrease 5.6 ng/mL) and PSA density (median decrease 0.14 ng/mL/cc) were observed (P < .01). At 6 months, 23 patients (79%) demonstrated no residual cancer on follow-up MRI-guided biopsy of the treated side. Three patients (10%) revealed micro-residual disease. Three patients (10%) had residual cancer and underwent further treatment. Ipsilateral MRI lesions were present before treatment in 26 patients and after treatment in only 2, reflecting the gross ablative effect; however, MRI showed disappearance of lesions in 4 patients with residual tumor on biopsy. The single complication was 1 case of transient urinary retention; 85% of men who were sexually active continued without change after treatment. Voiding function was unchanged.

CONCLUSION

Hemi-gland cryoablation for clinically-significant CaP is well-tolerated, and when patients are selected and followed by MRI/US fusion biopsy, cancer control appears promising at 6 months.

The Learning Curve for Magnetic Resonance Imaging/Ultrasound Fusion-guided Prostate Biopsy

BACKGROUND

Magnetic resonance imaging/ultrasound-guided fusion biopsy (FBx) is more accurate at detecting clinically significant prostate cancer than conventional transrectal ultrasound-guided systematic biopsy. However, learning curves for attaining accuracy may limit the generalizability of published outcomes.

OBJECTIVE

To delineate and quantify the learning curve for FBx by assessing the targeted biopsy accuracy and pathological quality of systematic biopsy over time.

DESIGN, SETTING, AND PARTICIPANTS

We carried out a retrospective analysis of 173 consecutive men who underwent Artemis FBx with computer-template systematic sampling between July 2015 and May 2017.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

The accuracy of targeted biopsy was determined by calculating the distance between planned and actual core trajectories stored on Artemis. Systematic sampling proficiency was assessed via pathological analysis of fibromuscular tissue in all cores and then comparing pathology elements from individual cores from men in the first and last tertiles. Polynomial linear regression models, change-point analysis, and piecewise linear regression were used to quantify the learning curve.

RESULTS AND LIMITATION

A significant improvement in targeted biopsy accuracy occurred up to 98 cases (p<0.01). There was a significant decrease in fibromuscular tissue in the systematic biopsy cores up to 84 cases (p<0.01) and an improvement in pathological quality when comparing systematic cores from the first and third tertiles. Use of a different fusion platform may limit the generalizability of our results.

CONCLUSIONS

There is a significant learning curve for targeted and systemic biopsy using the Artemis platform. Improvements in accuracy of targeted biopsy and better sampling for systematic biopsy can be achieved with greater experience.

PATIENT SUMMARY

We define the learning curve for magnetic resonance imaging/ultrasound-guided fusion biopsy (FBx) using targeted biopsy accuracy and systematic core sampling quality as measures. Our findings underscore the importance of overcoming learning curves inherent to FBx to minimize patient discomfort and biopsy risk and improve the quality of care for accurate risk stratification, active surveillance, and treatment selection.

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.

Targeted Prostate Biopsy in the Era of Active Surveillance

Targeted prostate biopsy using magnetic resonance imaging (MRI) guidance is improving the accuracy of prostate cancer (CaP) diagnosis. This new biopsy technology is especially important for men undergoing active surveillance, improving patient selection for enrollment and enabling precise longitudinal monitoring. Magnetic resonance imaging/ultrasound fusion biopsy allows for 3 functions not previously possible with US-guided biopsy: targeting of suspicious regions, template-mapping for systematic sampling, and tracking of cancer foci over time. This article reviews the evolving role of the new biopsy methods in active surveillance, including the UCLA Active Surveillance pathway, which has incorporated magnetic resonance imaging/ultrasound fusion biopsy from program inception as a possible model.