Erik Rud

Magnetic Resonance Imaging–Transectal Ultrasound Image-fusion Biopsies Accurately Characterize the Index Tumor: Correlation with Step-sectioned Radical Prostatectomy Specimens in 135 Patients

BACKGROUND Prostate biopsies targeted by elastic fusion of magnetic resonance (MR) and three-dimensional (3D) transrectal ultrasound (TRUS) images may allow accurate identification of the index tumor (IT), defined as the lesion with the highest Gleason score or the largest volume or extraprostatic extension. OBJECTIVE To determine the accuracy of MR-TRUS image-fusion biopsy in characterizing ITs, as confirmed by correlation with step-sectioned radical prostatectomy (RP) specimens. DESIGN, SETTING, AND PARTICIPANTS Retrospective analysis of 135 consecutive patients who sequentially underwent pre-biopsy MR, MR-TRUS image-fusion biopsy, and robotic RP at two centers between January 2010 and September 2013. INTERVENTION Image-guided biopsies of MR-suspected IT lesions were performed with tracking via real-time 3D TRUS. The largest geographically distinct cancer focus (IT lesion) was independently registered on step-sectioned RP specimens. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS A validated schema comprising 27 regions of interest was used to identify the IT center location on MR images and in RP specimens, as well as the location of the midpoint of the biopsy trajectory, and variables were correlated. RESULTS AND LIMITATIONS The concordance between IT location on biopsy and RP specimens was 95% (128/135). The coefficient for correlation between IT volume on MRI and histology was r=0.663 (p<0.001). The maximum cancer core length on biopsy was weakly correlated with RP tumor volume (r=0.466, p<0.001). The concordance of primary Gleason pattern between targeted biopsy and RP specimens was 90% (115/128; κ=0.76). The study limitations include retrospective evaluation of a selected patient population, which limits the generalizability of the results. CONCLUSION Use of MR-TRUS image fusion to guide prostate biopsies reliably identified the location and primary Gleason pattern of the IT lesion in >90% of patients, but showed limited ability to predict cancer volume, as confirmed by step-sectioned RP specimens. PATIENT SUMMARY Biopsies targeted using magnetic resonance images combined with real-time three-dimensional transrectal ultrasound allowed us to reliably identify the spatial location of the most important tumor in prostate cancer and characterize its aggressiveness.

A Randomized Controlled Trial To Assess and Compare the Outcomes of Two-core Prostate Biopsy Guided by Fused Magnetic Resonance and Transrectal Ultrasound Images and Traditional 12-core Systematic Biopsy.

BACKGROUND Prostate biopsy guided by computer-assisted fusion of magnetic resonance imaging (MRI) and transrectal ultrasound (TRUS) images (MRI group) has not yet been compared with 12-core random biopsy (RB; control group) in a randomized controlled trial (RCT). OBJECTIVE To compare the rate of detection of clinically significant prostate cancer (csPCa) between the two groups. DESIGN, SETTING, AND PARTICIPANTS This RCT included 175 biopsy-naïve patients with suspicion for prostate cancer, randomized to an MRI group (n=86) and a control group (n=89) between September 2011 and June 2013. INTERVENTION In the MRI group, two-core targeted biopsy (TB) guided by computer-assisted fusion of MRI/TRUS images of MRI-suspicious lesions was followed by 12-core RB. In the control group, both two-core TB for abnormal digital rectal examination (DRE) and/or TRUS-suspicious lesions and 12-core RB were performed. In patients with normal MRI or DRE/TRUS, only 12-core RB was performed. OUTCOMES MEASUREMENTS AND STATISTICAL ANALYSIS The detection rates for any cancer and csPCa were compared between the two groups and between TB and RB. RESULTS AND LIMITATIONS Detection rates for any cancer (MRI group 51/86, 59%; control group 48/89, 54%; p=0.4) and csPCa (38/86, 44% vs 44/89, 49%; p=0.5) did not significantly differ between the groups. Detection of csPCa was comparable between two-core MRI/TRUS-TB (33/86, 38%) and 12-core RB in the control group (44/89, 49%; p=0.2). In a subset analysis of patients with normal DRE, csPCa detection was similar between two-core MRI/TRUS-TB (14/66, 21%) and 12-core RB in the control group (15/60, 25%; p=0.7). Among biopsy-proven csPCas in MRI group, 87% (33/38) were detected by MRI/TRUS-TB. The definition of csPCa was only based on biopsy outcomes. CONCLUSION Overall csPCa detection was similar between the MRI and control groups. Two-core MRI/TRUS-TB was comparable to 12-core RB for csPCa detection. PATIENT SUMMARY Our randomized controlled trial revealed a similar rate of prostate cancer detection between targeted biopsy guided by magnetic resonance imaging (MRI) and transrectal ultrasound (TRUS) and 12-core random biopsy. The traditional 12-core random biopsy may be replaced by two-core MRI/TRUS targeted biopsy for detection of clinically significant prostate cancer.

Detection of the index tumour and tumour volume in prostate cancer using T2-weighted and diffusion-weighted magnetic resonance imaging (MRI) alone

To examine the performance of T2‐weighted (T2W) and diffusion‐weighted (DW) magnetic resonance imaging (MRI) for detecting the index tumour in patients with prostate cancer and to examine the agreement between MRI and histology when assessing tumour volume (TV) and overall tumour burden.

Predictive Value of Magnetic Resonance Imaging Determined Tumor Contact Length for Extracapsular Extension of Prostate Cancer

PURPOSE Tumor contact length is defined as the amount of prostate cancer in contact with the prostatic capsule. We evaluated the ability of magnetic resonance imaging determined tumor contact length to predict microscopic extracapsular extension compared to existing predictors of extracapsular extension. MATERIALS AND METHODS We retrospectively analyzed the records of 111 consecutive patients with magnetic resonance imaging/ultrasound fusion targeted, biopsy proven prostate cancer who underwent radical prostatectomy from January 2010 to July 2013. Median patient age was 64 years and median prostate specific antigen was 8.9 ng/ml. Clinical stage was cT1 in 93 cases (84%) and cT2 in 18 (16%). Postoperative pathological analysis confirmed pT2 in 71 patients (64%) and pT3 in 40 (36%). We evaluated 1) in the radical prostatectomy specimen the correlation of microscopic extracapsular extension with pathological cancer volume, pathological tumor contact length and Gleason score, 2) the correlation between microscopic extracapsular extension and magnetic resonance imaging tumor contact length, and 3) the ability of preoperative variables to predict microscopic extracapsular extension. RESULTS Logistic regression analysis revealed that pathological tumor contact length correlated better with microscopic extracapsular extension than the predictive power of pathological cancer volume (0.821 vs 0.685). The Spearman correlation between pathological and magnetic resonance imaging tumor contact length was r = 0.839 (p <0.0001). ROC AUC analysis revealed that magnetic resonance imaging tumor contact length outperformed cancer core involvement on targeted biopsy and the Partin tables to predict microscopic extracapsular extension (0.88 vs 0.70 and 0.63, respectively). At a magnetic resonance imaging tumor contact length threshold of 20 mm the accuracy for diagnosing microscopic extracapsular extension was superior to that of conventional magnetic resonance imaging criteria (82% vs 67%, p = 0.015). We developed a predicted probability plot curve of extracapsular extension according to magnetic resonance imaging tumor contact length. CONCLUSIONS Magnetic resonance imaging determined tumor contact length could be a promising quantitative predictor of microscopic extracapsular extension.

Hemi salvage high-intensity focused ultrasound (HIFU) in unilateral radiorecurrent prostate cancer: a prospective two-centre study

To report the oncological and functional outcomes of hemi salvage high‐intensity focused ultrasound (HSH) in patients with unilateral radiorecurrent prostate cancer.

Does Preoperative Magnetic Resonance Imaging Reduce the Rate of Positive Surgical Margins at Radical Prostatectomy in a Randomised Clinical Trial

BACKGROUND Magnetic resonance imaging (MRI) has the potential to help the surgeon tailor radical prostatectomy (RP) more accurately according to the location and extent of the tumour and thereby reduce the rate of positive surgical margins (PSMs). OBJECTIVE To evaluate the benefit of performing MRI prior to RP. DESIGN, SETTING, AND PARTICIPANTS This single-institution randomised trial included 438 patients between December 2009 and June 2012 who were scheduled for robot-assisted laparoscopic prostatectomy. The study was registered (ClinicalTrials.gov identifier NCT01347320). INTERVENTION Patients were preoperatively randomly assigned to non-MRI or MRI groups. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS The primary end point was the difference in the PSM rates between the two groups. Secondary end points were the rates of PSMs in clinical subgroups. Summary statistics were extracted from descriptive analyses, chi-square, or Fisher exact test, and logistic regression was used to analyse the data according to the intention-to-treat principle. RESULTS AND LIMITATIONS A total of 216 patients were randomised to non-MRI; 222 were randomised to MRI. There were 49 cases (23%) of PSMs in the non-MRI group and 43 cases (19%) in the MRI group (p=0.4). The relative and absolute risk reduction was 15% and 4%, respectively. Patients with cT1 constituted 55% of the cohort, in which the rate of PSMs was 27% in the non-MRI group and 16% in the MRI group (p=0.035). The relative and absolute risk reduction was 41% and 11%, respectively. A limitation was suboptimal communication between the radiologist and urologist. CONCLUSIONS MRI prior to RP did not reduce the overall risk for PSMs in this patient cohort. However, at subgroup analysis we observed a possible benefit of MRI in patients with cT1. PATIENT SUMMARY This study could not demonstrate a definite benefit of performing magnetic resonance imaging before surgery for all patients. However, there was a possible improved result in patients in which physical examination could not detect the cancer.

Effect of targeted biopsy guided by elastic image fusion of MRI with 3D-TRUS on diagnosis of anterior prostate cancer

PURPOSE To evaluate the effect of targeted biopsy (TB) with elastic fused magnetic resonance imaging (MRI) and 3-dimensional transrectal ultrasound (3D-TRUS) guidance in the diagnosis of anterior prostate cancer (APCa). MATERIAL AND METHOD A retrospective study was performed on patients who underwent TB with elastic fused MRI/3D-TRUS guidance using a 1.5-T MRI with T2- and diffusion-weighted images. APCa was defined as TB-proven cancer whose MR-imaged center was located anteriorly according to standardized MRI reporting schema. Prostate Imaging Reporting and Data System was used to quantify MRI suspicion. Maximum cancer core length (MCCL), cancer core involvement, primary Gleason grade pattern, and Gleason score (GS) on TB were assessed. A clinically significant cancer on TB was MCCL ≥ 5mm of GS 6 or any cancer with GS ≥ 7. Agreement between TB and radical prostatectomy step sections was assessed for all subjects when possible. RESULTS A total of 211 consecutive subjects were included. APCa was found in 81% (170/211). Median (range) of TB per patient, MCCL, and cancer core involvement were 2 (1-5), 10mm (4-23), and 57% (10%-100%), respectively. According to the level of MRI suspicion, positive rate for any cancer vs. clinically significant cancer was 96% (114/119) vs. 86% (102/119) for highly suspicious, 80% (46/57) vs. 68% (39/57) for likely, and 29% (10/35) vs. 20% (7/35) for equivocal, respectively (P = 0.016 and<0.001). Step-section analysis was possible for 70 patients. Concordance of primary Gleason grade pattern and GS between TB and radical prostatectomy was 90% (κ = 0.7) and 77% (κ = 0.64), respectively. CONCLUSION TB with elastic fused MRI/3D-TRUS guidance significantly enhanced accuracy in diagnosing clinically significant APCa.

Detection of Radiorecurrent Prostate Cancer Using Diffusion-Weighted Imaging and Targeted Biopsies

OBJECTIVE The primary purpose of this study was to evaluate the detection rate of local radiorecurrent prostate cancer by using diffusion-weighted MR imaging (DWI) and targeted biopsies. The secondary purpose was to assess the value of performing random biopsies. MATERIALS AND METHODS This study included 42 consecutive patients with biochemical recurrence after external beam radiation therapy (EBRT). At the time of biopsy, the mean age±SD was 67±6 years, median serum prostate-specific antigen level was 4.0±3.0 ng/mL, and mean elapsed time between EBRT and biopsy was 5.6±2.8 years. MRI examination included high-resolution axial T2-weighted and DWI sequences and was classified as either negative or positive. Transrectal ultrasound-guided targeted biopsies were obtained from all patients with positive findings on MRI using a soft image fusion system. Random sextant biopsies were obtained from both lobes in patients with negative findings on MRI and from the lobe contralateral to the MRI target in patients with positive findings on MRI. The biopsy results were classified as negative or positive and defined as the criterion standard. RESULTS MRI findings were positive in 40 of 42 (95%) patients, and the overall positive biopsy rate was 79% (33 of 42 patients). Targeted biopsies were positive in 33 of 40 (83%) patients. Random biopsies were positive in 6 of 30 (20%) patients, all of whom had positive targeted biopsies. CONCLUSION DWI is highly sensitive for detecting radiorecurrent prostate cancer, and a few targeted biopsies may confirm a positive diagnosis. However, random biopsies may assess the tumor burden more exactly.

Re: Jeffrey C. Weinreb, Jelle O. Barentsz, Peter L. Choyke, et al. PI-RADS Prostate Imaging – Reporting and Data System: 2015, Version 2. Eur Urol 2016;69:16–40: Is Contrast-enhanced Magnetic Resonance Imaging Really Necessary When Searching for Prostate Cancer?

We would like to commend the authors of PI-RADS v2 for greatly improving the recommendations for magnetic resonance imaging (MRI) interpretation and reporting compared to PI-RADS v1. However, we were surprised to see that dynamic contrast-enhanced (DCE) MRI is still recommended as part of multiparametric MRI examinations [1]. This is unexpected given the available level of evidence. The question is simple: which important studies have shown that DCE MRI offers any added benefit compared to T2-weighted images and diffusion-weighted images alone? The results of meta-analyses are traditionally ranked very highly when providing general recommendations. Two meta-analyses actually demonstrate that DCE MRI does not improve detection compared to T2-weighted and diffusion-weighted images alone [2,3], but none of these studies were included in the reference list. In addition, studies have shown that DCE MRI does not improve cancer volume estimation [4] and is unreliable for assessing cancer aggressiveness. Last but not least, DCE MRI does not improve staging [5]. Although the authors do acknowledge that the value of DCE MRI is probably minor, they still recommend contrast for all patients because it is believed that PI-RADS 3 lesions are better characterized when using contrast. Which studies support this statement? And why not perform a targeted biopsy for all PIRADS 3 lesions instead of complicating the MRI examination for all patients?

How Do We Select Patients Eligible for Focal Therapy? Imaging and Targeted Biopsies: A Basic Prerequisite for Focal Therapy

Aims of this chapter are to highlight the following: The concept of significant and insignificant cancer The importance of identifying the index tumor Benefits and limitations of MRI Optimal biopsy strategy