P. Puech

Role of magnetic resonance imaging before initial biopsy: comparison of magnetic resonance imaging-targeted and systematic biopsy for significant prostate cancer detection.

Study Type – Diagnostic (exploratory cohort)

Standards of Reporting for MRI-targeted Biopsy Studies (START) of the Prostate: Recommendations from an International Working Group.

BACKGROUND A systematic literature review of magnetic resonance imaging (MRI)-targeted prostate biopsy demonstrates poor adherence to the Standards for the Reporting of Diagnostic Accuracy (STARD) recommendations for the full and transparent reporting of diagnostic studies. OBJECTIVE To define and recommend Standards of Reporting for MRI-targeted Biopsy Studies (START). DESIGN, SETTING, AND PARTICIPANTS Each member of a panel of 23 experts in urology, radiology, histopathology, and methodology used the RAND/UCLA appropriateness methodology to score a 258-statement premeeting questionnaire. The collated responses were presented at a face-to-face meeting, and each statement was rescored after group discussion. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS Measures of agreement and consensus were calculated for each statement. The most important statements, based on group median score, the degree of group consensus, and the content of the group discussion, were used to create a checklist of reporting criteria (the START checklist). RESULTS AND LIMITATIONS The strongest recommendations were to report histologic results of standard and targeted cores separately using Gleason score and maximum cancer core length. A table comparing detection rates of clinically significant and clinically insignificant disease by targeted and standard approaches should also be used. It was recommended to report the recruitment criteria for MRI-targeted biopsy, prior biopsy status of the population, a brief description of the MRI sequences, MRI reporting method, radiologist experience, and image registration technique. There was uncertainty about which histologic criteria constitute clinically significant cancer when the prostate is sampled using MRI-targeted biopsy, and it was agreed that a new definition of clinical significance in this setting needed to be derived in future studies. CONCLUSIONS Use of the START checklist would improve the quality of reporting in MRI-targeted biopsy studies and facilitate a comparison between standard and MRI-targeted approaches.

Prostate Cancer Diagnosis: Multiparametric MR-targeted Biopsy with Cognitive and Transrectal US–MR Fusion Guidance versus Systematic Biopsy—Prospective Multicenter Study

PURPOSE To compare biopsy performance of two approaches for multiparametric magnetic resonance (MR)-targeted biopsy (TB) with that of extended systematic biopsy (SB) in prostate cancer (PCa) detection. MATERIALS AND METHODS This institutional review board-approved multicenter prospective study (May 2009 to January 2011) included 95 patients with informed consent who were suspected of having PCa, with a suspicious abnormality (target) at prebiopsy MR. Patients underwent 12-core SB and four-core TB with transrectal ultrasonographic (US) guidance, with two cores aimed visually (cognitive TB [TB-COG]) and two cores aimed using transrectal US-MR fusion software (fusion-guided TB [TB-FUS]). SB and TB positivity for cancer and sampling quality (mean longest core cancer length, Gleason score) were compared. Clinically significant PCa was any 3 mm or greater core cancer length or any greater than 3 Gleason pattern for SB or any cancer length for TB. Statistical analysis included t test, paired χ(2) test, and κ statistic. Primary end point (core cancer length) was calculated (paired t test). RESULTS Among 95 patients (median age, 65 years; mean prostate-specific antigen level, 10.05 ng/mL [10.05 μg/L]), positivity rate for PCa was 59% (n = 56) for SB and 69% (n = 66) for TB (P = .033); rate for clinically significant PCa was 52% (n = 49) for SB and 67% (n = 64) for TB (P = .0011). Cancer was diagnosed through TB in 16 patients (17%) with negative SB results. Mean longest core cancer lengths were 4.6 mm for SB and 7.3 mm for TB (P < .0001). In 12 of 51 (24%) MR imaging targets with positive SB and TB results, TB led to Gleason score upgrading. In 79 MR imaging targets, positivity for cancer was 47% (n = 37) with TB-COG and 53% (n = 42) with TB-FUS (P = .16). Neither technique was superior for Gleason score assessment. CONCLUSION Prebiopsy MR imaging combined with transrectal US-guided TB increases biopsy performance in detecting PCa, especially clinically significant PCa. No significant difference was observed between TB-FUS and TB-COG for TB guidance.

Dynamic contrast-enhanced-magnetic resonance imaging evaluation of intraprostatic prostate cancer: correlation with radical prostatectomy specimens.

OBJECTIVES To determine the diagnostic performance of dynamic contrast-enhanced-magnetic resonance imaging (DCE-MRI) in the identification of intraprostatic cancer foci related to cancer volume at histopathology, in patients with clinically localized cancer treated by radical prostatectomy, with whole-mount histopathologic sections as the reference standard. METHODS Eighty-three consecutive radical prostatectomy specimens from patients referred for a prostate-specific antigen elevation were correlated with prebiopsy MRI. MRI results ranked on a 5-point scale were correlated with the findings of histopathology maps in 8 prostate sectors, including volume, largest surface area, and percentage of Gleason grade 4/5. The area under the receiver operating characteristic curve was used. RESULTS Median prostate-specific antigen was 8.15 ng/mL. DCE-MRI was suspicious in 55 (66%) out of 83 patients. A separate cancer foci (mean 2.55 per patient) was present in 212 (34%) of 664 octants and DCE-MRI was suspicious in 68 of 212. Sensitivity and specificity of DCE-MRI at score 3.4 or 5 for identification of cancer foci at any volume was 32% and 95%, respectively. For identification of cancer foci > 0.5 mL, the sensitivity and specificity were 86% and 94%, respectively, with the under the receiver operating characteristic curve of 0.874. Mean volume of DCE-MRI detected and missed cancers were 2.44 mL (0.02-14.5) and 0.16 mL (0.005-2.4), respectively. Sensitivity and specificity of DCE-MRI for identification of > 10% of Gleason grade 4/5 were 81% and 82%, respectively. CONCLUSIONS DCE-MRI can accurately identify intraprostatic cancer foci. Possible applications are guidance for biopsies, selection of patients for watchful waiting, and focal treatment planning.

Combined Multiparametric MRI and Targeted Biopsies Improve Anterior Prostate Cancer Detection, Staging, and Grading

OBJECTIVES To assess the efficacy of magnetic resonance imaging (MRI) in detection of suspicious anterior prostate lesions, and its role in staging and grading of anterior prostate cancer (APC). METHODS Between January 2008 and August 2009, 243 patients had prostate cancer diagnosed at 12-cores posterior systematic biopsies and additional 2-cores transrectal ultrasound-guided, free-hand-targeted biopsy at any area suspicious for malignancy at prebiopsy multiparametric MRI. We conducted a retrospective study of 45 of 243 (19%) patients with an area suspicious for malignancy at MRI predominantly located in the anterior part of the gland, for which targeted biopsies were positive. Targeted vs systematic biopsy cancer detection rate and upgrading based on length of cancer in the most involved core and Gleason score were measured. RESULTS Of the 45 patients, 46 separate APCs were identified at MRI with positive targeted biopsies. APC was not detected by systematic biopsies in 21 (46%) cases and detected in 25 (54%) cases. For these 25 cases, median cancer length of the most involved core in targeted compared with systematic biopsies was 8 mm vs 1 mm (P <.001), respectively. Significant Gleason score upgrading was observed in 11 of 25 (44%) cases. Correlation coefficient between the cancer length on targeted biopsies and the antero-posterior diameter of the area suspicious for malignancy on MRI was r(2) = .6 (P <.001). Separate posterior cancer was diagnosed in 26 patients. CONCLUSIONS Targeted biopsies based on a prebiopsy MRI-detected lesion improved detection rate, volume, and grade of APC compared with currently used 12-cores systematic biopsies.

Current status of MRI for the diagnosis, staging and prognosis of prostate cancer: implications for focal therapy and active surveillance.

Purpose of review To review the current status of MRI techniques in identification of organ-confined prostate cancer with a focus on their implication for focal therapy and active surveillance. Recent findings MRI is currently focusing on intraprostatic prostate cancer identification and at 1.5T, it provides excellent imaging of the whole gland including the challenging anterior part. Improvements in accuracy for cancer detection and volume estimation result from dynamic contrast-enhanced and diffusion-weighted MRI sequences. 3T MRI might improve cancer identification. Histological correlations showed high sensitivity and specificity for significant volume cancers larger than 0.5 cm3. Important knowledge on modelling of cancer morphology such as zone of origin and intraprostatic patterns of spread at histopathology was made available for imaging interpretation and treatment planning decision. MRI results allow focused use of biopsy which led to better cancer characterization such as extent and grade. Ongoing focal therapy protocols and active surveillance treatments should benefit from these imaging advances. Summary At present, high-resolution MRI with pelvic coil appears to offer the most readily available and useful imaging. Future studies should work towards helping define standard, reproducible approaches to imaging and image reporting for research and clinical practice.

Scoring systems used for the interpretation and reporting of multiparametric MRI for prostate cancer detection, localization, and characterization: could standardization lead to improved utilization of imaging within the diagnostic pathway?

Multiparametric magnetic resonance imaging (mpMRI) is increasingly being used earlier in the prostate cancer diagnostic pathway in order to detect and localize disease. Its results can be used to help decide on the indication, type, and localization of a prostate biopsy for cancer diagnosis. In addition, mpMRI has the potential to contribute information on the characterization, or aggressiveness, of detected cancers including tumor progression over time. There is considerable variation in the way results of different MRI sequences are reported. We conducted a review of scoring systems that have been used in the detection and characterization of prostate cancer. This revealed that existing scoring and reporting systems differ in purpose, scale, and range. We evaluate these differences in this review. This first step in collating all methods of scoring and reporting mpMRI will ultimately lead to consensus approaches to develop a standardized reporting scheme that can be widely adopted and validated to ensure comparability of research outputs and optimal clinical practice. J. Magn. Reson. Imaging 2013;37:48–58.

Transition zone and anterior stromal prostate cancers: Zone of origin and intraprostatic patterns of spread at histopathology

To describe the precise location of transition zone (TZ) and anterior fibromuscular stroma (AFMS) prostate cancers (TZ/AFMS) within histological zones at various stages of development and to demonstrate their pattern of intraprostatic spread from their site of origin.

Peripheral zone prostate cancers: location and intraprostatic patterns of spread at histopathology.

To describe the precise location of peripheral zone (PZ) prostate cancers at various stages of development and to demonstrate their pattern of intraprostatic spread from their site of origin.

Imaging of organ-confined prostate cancer: functional ultrasound, MRI and PET/computed tomography.

Purpose of review To review the current status of advanced imaging techniques in identification of organ-confined prostate cancer with a focus on their impact on patient management. Recent findings Transrectal ultrasound suffers from poor accuracy despite significant technical improvements. Generally used to distinguish cancers with extraprostatic spread, MRI is now focusing on intraprostatic prostate cancer identification. At 1.5T, the most recent high-resolution pelvic phased-array coils provide excellent imaging of the whole gland, including this challenging anterior part. Improvements in accuracy for cancer detection and volume estimation result from dynamic contrast-enhanced and diffusion-weighted imaging sequences. Histological correlations showed high sensitivity/specificity for significant volume cancers. 3T MRI scanners will improve these results. Most of the recent PET/computed tomography imaging studies use choline derivatives (11C-choline and 18F-fluorocholine). Their results are promising but insufficient to be currently recommended in routine practice. Summary Considerable advances have been made in the identification of organ-confined prostate cancer with multiparametric MRI. Only prebiopsy MRI can provide best quality of cancer assessment and allows for targeting biopsies. It is hoped that advances in 3T MRI as well as in radiotracers for PET/computed tomography will further improve diagnosis, treatment selection, planning and outcomes.