Mr Joseph Norris is a Specialty Registrar in Urology in the London Deanery. He is currently undertaking an MRC Doctoral Fellowship at UCL, under the supervision of Professor Mark Emberton. His research interest is prostate cancer that is inconspicuous on mpMRI.
Every week, the Editor-in-Chief selects an Article of the Week from the current issue of BJUI. The abstract is reproduced below and you can click on the button to read the full article, which is freely available to all readers for at least 30 days from the time of this post.
In addition to the article itself, there is an editorial written by a prominent member of the urological community and a video prepared by the authors. These are intended to provoke comment and discussion and we invite you to use the comment tools at the bottom of each post to join the conversation.
If you only have time to read one article this week, it should be this one.
Jonathan B. Bloom*, Amir H. Lebastchi*, Samuel A. Gold*, Graham R. Hale*, Thomas Sanford*†, Sherif Mehralivand*†‡, Michael Ahdoot*, Kareem N. Rayn*, Marcin Czarniecki†, Clayton Smith†, Vladimir Valera*, Bradford J. Wood§, Maria J. Merino¶, Peter L. Choyke†, Howard L. Parnes**, Baris Turkbey† and Peter A. Pinto*§
*Urologic Oncology Branch, †Molecular Imaging Program, NCI, NIH, Bethesda, MD, USA, ‡Department of Urology and Pediatric Urology, University Medical Center Mainz, Mainz, Germany, §Center for Interventional Oncology, ¶Laboratory of Pathology, and **Division of Cancer Prevention, NCI, NIH, Bethesda, MD, USA
To determine the rate of Gleason Grade Group (GGG) upgrading in African‐American (AA) men with a prior diagnosis of low‐grade prostate cancer (GGG 1 or GGG 2) on 12‐core systematic biopsy (SB) after multiparametric magnetic resonance imaging (mpMRI) and fusion biopsy (FB); and whether AA men who continued active surveillance (AS) after mpMRI and FB fared differently than a predominantly Caucasian (non‐AA) population.
A database of men who had undergone mpMRI and FB was queried to determine rates of upgrading by FB amongst men deemed to be AS candidates based on SB prior to referral. After FB, Kaplan–Meier curves were generated for AA men and non‐AA men who then elected AS. The time to GGG upgrading and time continuing AS were compared using the log‐rank test.
AA men referred with GGG 1 disease on previous SB were upgraded to GGG ≥3 by FB more often than non‐AA men, 22.2% vs 12.7% (P = 0.01). A total of 32 AA men and 258 non‐AA men then continued AS, with a median (interquartile range) follow‐up of 39.19 (24.24–56.41) months. The median time to progression was 59.7 and 60.5 months, respectively (P = 0.26). The median time continuing AS was 61.9 months and not reached, respectively (P = 0.80).
AA men were more likely to be upgraded from GGG 1 on SB to GGG ≥3 on initial FB; however, AA and non‐AA men on AS subsequently progressed at similar rates following mpMRI and FB. A greater tendency for SB to underestimate tumour grade in AA men may explain prior studies that have shown AA men to be at higher risk of progression during AS.
This timely and important article by Bloom et al. [1] highlights findings that warrant special attention in an effort to address and reduce racial disparities in low‐risk prostate cancer. At the population level, African‐American (AA) men are 76% more likely to be diagnosed with prostate cancer and 2.2‐times more likely to die from prostate cancer compared with other men in the USA. Emerging evidence suggests that racial disparities in patients diagnosed with advanced stage or higher‐risk disease may be predominantly accounted for by social factors and healthcare access [1,2]. In contrast, there is growing evidence that raises the question of whether disparities in low‐risk disease may be driven by underlying tumour and/or biopsy misclassification differences [2,3,4].
Bloom et al. [1] examined a USA study cohort from the National Cancer Institute (NCI) and found that amongst men referred to the NCI with a prior 12‐core systematic biopsy (SB), AA men with Gleason Grade (GG) 1 disease were nearly twice as likely to be upgraded by targeted multiparametric (mp)MRI fusion‐guided biopsy when compared with non‐AA men. These findings are consistent with contemporary data in the USA‐based Surveillance, Epidemiology and End Results Program, where amongst 20 125 men (including 2594 AA men) with clinical National Comprehensive Cancer Network (NCCN) low‐risk prostate cancer (GG 1 on biopsy) who underwent radical prostatectomy (RP) from 2010 to 2015, AA men were more likely to have pathological upgrading at the time of RP when compared with non‐AA men (47.3% vs 45.3%; adjusted hazard ratio 1.12, 95% CI 1.03–1.22, P = 0.007; unpublished analysis). Furthermore, the study findings are consistent with prior work that has shown that AA men with NCCN very‐low‐risk disease who underwent RP were more likely to have disease upgrading at RP (27.3% vs 14.4%; P < 0.001), positive surgical margins (9.8% vs 5.9%; P = 0.02), and higher Cancer of the Prostate Risk Assessment Post‐Surgical scoring system (CAPRA‐S) scores [5]; notably these AA men with very‐low‐risk disease also had a distinct zonal distribution of prostate cancer when compared with other men, with anterior tumours that are more difficult to sample by standard 12‐core SB alone [3].
Although low‐grade/risk disease is considered prognostically favourable and can be managed conservatively with active surveillance (AS), racial differences in outcome and zonal distribution of disease observed in favourable‐risk cohorts has led to controversy over the use of AS in AA men. Furthermore, conservative management trials have severely under‐represented patients of African descent. In this setting, most treatment guidelines advise caution when applying AS to AA patients. As such, although AS rates for low‐risk disease have nearly tripled in the USA from 14.5% to 42.1% from 2010 to 2015, there is lower relative uptake of AS for AA men compared with other men, even after adjusting for socioeconomic status, suggesting that providers and patients may be ‘risk‐stratifying’ AA patients with low‐risk disease into a higher‐risk category, and therefore less willing to proceed with AS [6].
Ultimately, the application of AS to AA patients with low‐risk disease will remain controversial and providers will make decisions based on observational data until a representative trial can help answer: (i) whether AA men diagnosed with low‐risk disease who are eligible for AS might be more likely to have distinct aggressive disease features compared with non‐AA men, and (ii) whether there might be strategies, such as guided‐fusion biopsy and/or incorporation of tumour genomics prior to AS, to help identify AA patients with underlying aggressive disease and appropriately select AA men with low‐risk disease for AS protocols.
The most interesting and important result found by Bloom et al. [1] is that amongst men who underwent mpMRI fusion‐guided biopsy after initial diagnosis of low‐risk disease on SB and who ultimately were continued on AS (those who were upgraded at the time of fusion‐guided biopsy became ineligible for AS), AA and non‐AA men had similar progression rates on AS. This result suggests that incorporation of techniques such as mpMRI and fusion biopsy may help better select AA men for AS when compared with standard 12‐core SB. Specifically, MRI guided‐biopsy may reduce disparate misclassification errors by increasing detection of higher grade and more anterior tumours that are more likely to be found in AA men who initially present with low‐risk disease after standard SB. As such, this strategy may represent one mechanism to better select AA men for AS and therefore may be able to reduce disparities in low‐risk disease.
The authors should be applauded for their important work, and this study builds on a growing body of evidence that clearly demonstrates the need for prospective trials examining different diagnostic/prognostic strategies that may reduce disparities in low‐risk disease by more appropriately selecting AA men for AS strategies.
by Brandon A. Mahal (@BrandonMahal)
To determine the rate of Gleason Grade Group (GGG) upgrading in African‐American (AA) men with a prior diagnosis of low‐grade prostate cancer (GGG 1 or GGG 2) on 12‐core systematic biopsy (SB) after multiparametric magnetic resonance imaging (mpMRI) and fusion biopsy (FB); and whether AA men who continued active surveillance (AS) after mpMRI and FB fared differently than a predominantly Caucasian (non‐AA) population.
A database of men who had undergone mpMRI and FB was queried to determine rates of upgrading by FB amongst men deemed to be AS candidates based on SB prior to referral. After FB, Kaplan–Meier curves were generated for AA men and non‐AA men who then elected AS. The time to GGG upgrading and time continuing AS were compared using the log‐rank test.
AA men referred with GGG 1 disease on previous SB were upgraded to GGG ≥3 by FB more often than non‐AA men, 22.2% vs 12.7% (P = 0.01). A total of 32 AA men and 258 non‐AA men then continued AS, with a median (interquartile range) follow‐up of 39.19 (24.24–56.41) months. The median time to progression was 59.7 and 60.5 months, respectively (P = 0.26). The median time continuing AS was 61.9 months and not reached, respectively (P = 0.80).
AA men were more likely to be upgraded from GGG 1 on SB to GGG ≥3 on initial FB; however, AA and non‐AA men on AS subsequently progressed at similar rates following mpMRI and FB. A greater tendency for SB to underestimate tumour grade in AA men may explain prior studies that have shown AA men to be at higher risk of progression during AS.
Every week, the Editor-in-Chief selects an Article of the Week from the current issue of BJUI. The abstract is reproduced below and you can click on the button to read the full article, which is freely available to all readers for at least 30 days from the time of this post.
In addition to the article itself, there is an editorial written by a prominent member of the urological community and a video prepared by the authors. These are intended to provoke comment and discussion and we invite you to use the comment tools at the bottom of each post to join the conversation.
If you only have time to read one article this week, it should be this one.
Wulphert Venderink*, Annemarijke van Luijtelaar*, Marloes van der Leest*, Jelle O. Barentsz*, Sjoerd F.M. Jenniskens*, Michiel J.P. Sedelaar†,Christina Hulsbergen-van de Kaa‡, Christiaan G. Overduin* and Jurgen J. Fütterer*
*Department of Radiology and Nuclear Medicine, †Department of Urology, and ‡Department of Pathology, Radboud University Medical Center, Nijmegen, the Netherlands
To determine the proportion of men avoiding biopsy because of negative multiparametric magnetic resonance imaging (mpMRI) findings in a prostate MRI expert centre, and to assess the number of clinically significant prostate cancers (csPCa) detected during follow‐up.
Retrospective study of 4259 consecutive men having mpMRI of the prostate between January 2012 and December 2017, with either a history of previous negative transrectal ultrasonography‐guided biopsy or biopsy naïve. Patients underwent mpMRI in a referral centre. Lesions were classified according to Prostate Imaging Reporting And Data System (PI‐RADS) versions 1 and 2. Negative mpMRI was defined as an index lesion PI‐RADS ≤2. Follow‐up until 13 October 2018 was collected by searching the Dutch Pathology Registry (PALGA). Gleason score ≥3 + 4 was considered csPCa. Kaplan–Meier analysis and univariable logistic regression models were used in the cohort of patients with negative mpMRI and follow‐up.
Fig. 2. Distribution of PI‐RADS scored in the entire cohort.
Overall, in 53.6% (2281/4259) of patients had a lesion classified as PI‐RADS ≤2. In 320 patients with PI‐RADS 1 or 2, follow‐up mpMRI was obtained after a median (interquartile range) of 57 (41–63) months. In those patients, csPCa diagnosis‐free survival (DFS) was 99.6% after 3 years. Univariable logistic regression analysis revealed age as a predictor for csPCa during follow‐up (P < 0.05). In biopsied patients, csPCa was detected in 15.8% (19/120), 43.2% (228/528) and 74.5% (483/648) with PI‐RADS 3, 4 and 5, respectively.
More than half of patients having mpMRI of the prostate avoided biopsy. In those patients, csPCa DFS was 99.6% after 3 years.
In 2019 is it safe to avoid prostate biopsy in men with Prostate Imaging Reporting and Data System (PI‐RADS) score 1 and 2 lesions reported on their multiparametric MRI (mpMRI)? In this journal, Venderink et al. [1] suggest that more than half the men being investigated for suspected prostate cancer could indeed safely avoid an initial biopsy. However, like other investigators in this field, the authors make an assumption in their study that there is such a paucity of clinically significant cancer in men with PI‐RADS 1 and 2 lesions, that biopsy is not deemed necessary, as in the PRECISION study [2]. In this study [1] from the Netherlands, of the 2281 men with an initial diagnosis of PI‐RADS 1 or 2 lesions, only 320 men had follow‐up mpMRI, and biopsies were only performed in a small number of men with PI‐RADS scores ≥ 3. Whilst one could conclude that 84% of men did not progress, based on serial imaging, one cannot prove what may have been missed.
Comparing mpMRI of the prostate to the reference standard of radical prostatectomy whole‐mount specimens, a study from the University of California, Los Angeles showed that mpMRI can potentially miss up to 35% of clinically significant cancers, and up to 20% of high grade cancers. It found that 74% of missed solitary tumours were clinically significant, including 23% with Gleason ≥4 + 3 = 7, and that 38.7% were >1 cm in diameter [3]. As such, these missed cancers were not all small, low grade and clinically insignificant. An Italian study confirmed these findings with a detection rate of clinically significant prostate cancer outside the index lesion seen on mpMRI in 30% of patients [4]. All urologists are aware that biopsy by any means can never detect all the cancers seen on formal whole‐mount histopathology, but we do have evidence using transperineal prostate mapping biopsies as the reference standard as to what may be missed. The PROMIS study [5] provides the best evidence using several definitions of clinically significant cancer. Using Gleason ≥4 + 3 or cancer core length >6 mm the negative predictive value (NPV) of a negative mpMRI was 89%. However, if the criteria were altered to any Gleason 7 cancer, the NPV falls to 76%. This is also supported by a multicentre study by Hansen et al. [6], which demonstrated that the NPV of a negative mpMRI for excluding Gleason 7–10 cancer was 80%, but improved to 91% with a PSA density of <0.1 ng/mL/mL, and to 89% with a PSA density of <0.15 ng/mL/mL. It is important to note that these studies used transperineal biopsies rather than 12‐core transrectal biopsies, suggesting the latter to be a more unreliable reference test with a greater probability of missing clinically significant cancer on systematic sampling.
Are all Gleason 3 + 4 = 7 cancers < 6 mm in core length, for example, 5 mm Gleason 3 + 4 (40%) = 7 cancer, truly clinically insignificant? If that were the case, favourable intermediate‐risk prostate cancer would have to be an accepted indication for active surveillance (AS) in men, and in most cases this is not the case. National Comprehensive Cancer Network guidelines recommend that men with favourable intermediate‐risk prostate cancer should only be offered AS if the PSA is <10 ng/mL, the lesion is cT1 and the percentage of positive cores is <50%. Prostate Cancer Research International Active Surveillance (PRIAS) criteria only accept men with favourable intermediate‐risk prostate cancer if there is a maximum of two cores involved, PSA density is <0.2 ng/mL/mL, and if it represents <10% of the core. Both European Association of Urology and AUA guidelines caution that if men are offered AS with favourable intermediate‐risk disease, they should be warned of the greater risk of developing metastatic spread. It is therefore clear that major international guidelines do not fully support AS for intermediate‐risk prostate cancers and therefore it may not be acceptable to be missing Gleason 3 + 4 cancers in up to 10–20% of men with normal prostate mpMRI results.
Multiparametric MRI of the prostate has been a huge advance in prostate cancer diagnostics and is now widely used internationally, but does have limitations. Based on the available data, men who choose not to be biopsied with a normal prostate mpMRI should be warned, as part of informed consent, that a clinically significant cancer could be missed in up to 10–20% of cases (depending on PSA density) and close follow‐up should be recommended. One could easily argue that men with normal prostate mpMRI but with PSA density >0.15 ng/mL/mL should still be offered a systematic biopsy. Perhaps the future lies in the genomics of mpMRI‐visible vs ‐invisible lesions, with a recent study showing that there is a confluence of aggressive molecular and pathological features in lesions visible on MRI. Future research may be able to determine if indeed it is safe to leave some Gleason 3 + 4 = 7 cancers undetected if invisible on mpMRI because of their lack of genomic and metabolic aggression rather than based on their Gleason pattern [7].
by Mark Frydenberg
To determine the proportion of men avoiding biopsy because of negative multiparametric magnetic resonance imaging (mpMRI) findings in a prostate MRI expert centre, and to assess the number of clinically significant prostate cancers (csPCa) detected during follow‐up.
Retrospective study of 4259 consecutive men having mpMRI of the prostate between January 2012 and December 2017, with either a history of previous negative transrectal ultrasonography‐guided biopsy or biopsy naïve. Patients underwent mpMRI in a referral centre. Lesions were classified according to Prostate Imaging Reporting And Data System (PI‐RADS) versions 1 and 2. Negative mpMRI was defined as an index lesion PI‐RADS ≤2. Follow‐up until 13 October 2018 was collected by searching the Dutch Pathology Registry (PALGA). Gleason score ≥3 + 4 was considered csPCa. Kaplan–Meier analysis and univariable logistic regression models were used in the cohort of patients with negative mpMRI and follow‐up.
Overall, in 53.6% (2281/4259) of patients had a lesion classified as PI‐RADS ≤2. In 320 patients with PI‐RADS 1 or 2, follow‐up mpMRI was obtained after a median (interquartile range) of 57 (41–63) months. In those patients, csPCa diagnosis‐free survival (DFS) was 99.6% after 3 years. Univariable logistic regression analysis revealed age as a predictor for csPCa during follow‐up (P < 0.05). In biopsied patients, csPCa was detected in 15.8% (19/120), 43.2% (228/528) and 74.5% (483/648) with PI‐RADS 3, 4 and 5, respectively.
More than half of patients having mpMRI of the prostate avoided biopsy. In those patients, csPCa DFS was 99.6% after 3 years.
Every week, the Editor-in-Chief selects an Article of the Week from the current issue of BJUI. The abstract is reproduced below and you can click on the button to read the full article, which is freely available to all readers for at least 30 days from the time of this post.
In addition to the article itself, there is an editorial written by a prominent member of the urological community, and a video produced by the authors. These are intended to provoke comment and discussion and we invite you to use the comment tools at the bottom of each post to join the conversation.
If you only have time to read one article this week, it should be this one.
Mostafa Alabousi*, Jean-Paul Salameh†‡, Kaela Gusenbauer§, Lucy Samoilov¶, Ali Jafri**, Hang Yu§ and Abdullah Alabousi††
*Department of Radiology, McMaster University, Hamilton, †Department of Clinical Epidemiology and Public Health, University of Ottawa, ‡The Ottawa Hospital Research Institute, Clinical Epidemiology Program, Ottawa, §Department of Medicine, McMaster University, Hamilton, ¶Department of Medicine, Western University, London, ON, Canada, **Department of Medicine, New York Institute of Technology School of Osteopathic Medicine, Glen Head, NY, USA, and ††Department of Radiology, St Joseph’s Healthcare, McMaster University, Hamilton, ON, Canada
To perform a diagnostic test accuracy (DTA) systematic review and meta‐analysis comparing multiparametric (diffusion‐weighted imaging [DWI], T2‐weighted imaging [T2WI], and dynamic contrast‐enhanced [DCE] imaging) magnetic resonance imaging (mpMRI) and biparametric (DWI and T2WI) MRI (bpMRI) in detecting prostate cancer in treatment‐naïve patients.
The Medical Literature Analysis and Retrieval System Online (MEDLINE) and Excerpta Medica dataBASE (EMBASE) were searched to identify relevant studies published after 1 January 2012. Articles underwent title, abstract, and full‐text screening. Inclusion criteria consisted of patients with suspected prostate cancer, bpMRI and/or mpMRI as the index test(s), histopathology as the reference standard, and a DTA outcome measure. Methodological and DTA data were extracted. Risk of bias was assessed using the Quality Assessment of Diagnostic Accuracy Studies (QUADAS)‐2 tool. DTA metrics were pooled using bivariate random‐effects meta‐analysis. Subgroup analysis was conducted to assess for heterogeneity.
From an initial 3502 studies, 31 studies reporting on 9480 patients (4296 with prostate cancer) met the inclusion criteria for the meta‐analysis; 25 studies reported on mpMRI (7000 patients, 2954 with prostate cancer) and 12 studies reported on bpMRI DTA (2716 patients, 1477 with prostate cancer). Pooled summary statistics demonstrated no significant difference for sensitivity (mpMRI: 86%, 95% confidence interval [CI] 81–90; bpMRI: 90%, 95% CI 83–94) or specificity (mpMRI: 73%, 95% CI 64–81; bpMRI: 70%, 95% CI 42–83). The summary receiver operating characteristic curves were comparable for mpMRI (0.87) and bpMRI (0.90).
No significant difference in DTA was found between mpMRI and bpMRI in diagnosing prostate cancer in treatment‐naïve patients. Study heterogeneity warrants cautious interpretation of the results. With replication of our findings in dedicated validation studies, bpMRI may serve as a faster, cheaper, gadolinium‐free alternative to mpMRI.
Every week, the Editor-in-Chief selects an Article of the Week from the current issue of BJUI. The abstract is reproduced below and you can click on the button to read the full article, which is freely available to all readers for at least 30 days from the time of this post.
In addition to the article itself, there is an editorial written by a prominent member of the urological community. These are intended to provoke comment and discussion and we invite you to use the comment tools at the bottom of each post to join the conversation.
If you only have time to read one article this week, it should be this one.
To develop a clinical prediction tool that characterises the risk of missing significant prostate cancer by omitting systematic biopsy in men undergoing transrectal ultrasonography/magnetic resonance imaging (TRUS/MRI)‐fusion‐guided biopsy.
A consecutive sample of men undergoing TRUS/MRI‐fusion‐guided biopsy with the UroNav® system (Invivo International, Best, The Netherlands) who also underwent concurrent systematic biopsy was included. By comparing the grade of cancer diagnosed on targeted and systematic biopsy cores, we identified cases where clinically significant disease (Gleason score ≥3+4) was only found on systematic and not targeted cores. Multivariable logistic regression analyses were used to identify predictive factors for finding significant cancer on systematic cores only. We then used these data to develop a nomogram and evaluated its utility using decision curve analysis.
Fig 1. Nomogram for predicting the diagnosis of clinically significant on systematic biopsy only and missed on targeted biopsy.
Of the 398 men undergoing TRUS/MRI‐fusion‐guided biopsy in our study, there were 46 (11.6%) cases in which clinically significant cancer was missed on targeted biopsy and detected on systematic biopsy. The clinical setting, number of MRI lesions identified, and the highest Prostate Imaging‐Reporting and Data System (PI‐RADS) score of the lesions, were all found to be predictors of this. Our model had a good discriminative ability (concordance index = 0.70). The results from our decision curve analysis show that this model provides a higher net clinical benefit than either biopsying all men or omitting biopsy in all patients when the threshold probability is <30%.
We found that omitting concurrent systematic biopsy in men undergoing TRUS/MRI‐fusion‐guided biopsy would miss significant disease in more than one in 10 patients. We propose a prediction model with good discriminative ability that can be used to improve patient selection for performing concurrent systematic biopsy in order to minimise the number of missed significant cancers. It is important that our model is validated in external cohorts before being employed in routine clinical practice.
Sampling of prostate tissue to confirm pathologically a clinical suspicion of cancer has undergone an exponential change. The random systematic prostate biopsy technique was the only method used for many decades, initially guided by the finger but, since 1989, performed with TRUS guidance. Now, within the space of only a few years, we have entered the era of performing prostate biopsies on the basis of high‐tech three‐dimensional multiparametric MRI images, including software that can track the exact course of the biopsy needle [1]. While new technical developments in general lead to better, more individually directed healthcare, there is always the risk of abandoning ‘old’ but well developed and extensively tested techniques too soon. In this issue of the BJUI, Press et al. [2] looked at the added value of the presence of an ‘old‐fashioned’ TRUS‐detected lesion in cancer‐suspicious regions on MRI to better predict the presence of clinically significant prostate cancer (csPCa) defined as Gleason score ≥7. In their study comprising 1058 men, it was shown that a well‐demarcated abnormal TRUS finding noted at the time of MRI‐TRUS fusion‐guided prostate biopsy coincides with an increased risk of csPCa detection, independent of MRI suspicion (Prostate Imaging Reporting and Data System [PI‐RADS] score).
Increasing PI‐RADS score is correlated with an increased percentage of csPCa after targeted biopsy, both at initial and repeat biopsy. In a review based on data from 8252 men, it was shown that there is a gradual increase in the detection of csPCa from PI‐RADS 3 to PI‐RADS 4 to PI‐RADS 5 index lesions. For example, at first biopsy, the overall rate of PCa detection and the percentage of csPCa were 39%, 62% and 92% and 54%, 63% and 76% for PI‐RADS 3, 4 and 5 lesions, respectively. This means that in men with PI‐RADS 3 lesions, representing approximately one‐third of men deemed eligible for further assessment, only 39% will be diagnosed with PCa and half of the PCa detected will be potentially indolent Gleason 6 PCa [3]. This makes this group of men extremely interesting for further risk stratification before biopsy. Multivariable risk stratification in which PSA density plays an important role has been shown to be of value in these men [4] but further refinement could potentially be made by including suspicious lesions identified at TRUS.
Apart from the added value of TRUS findings in terms of risk stratification, the performance of the MRI‐targeted biopsy itself could be improved by visual guidance of hypoechoic lesions. In the present study by Press et al [2], a hypoechoic TRUS lesion was present at or near the location of two‐thirds of cancer‐suspicious lesions on MRI. The authors more or less advise to direct the targeted biopsy cores not only to the MRI suspicious lesion, but also the TRUS suspicious lesion, both of which often do not fully overlay in a software‐assisted MRI‐TRUS fusion model. The extent to which this ‘correction for misregistration’ is already included during targeted biopsy in current clinical practice is unknown. Although feasible and seemingly important during software‐assisted fusion targeted biopsy, TRUS lesions in cancer‐suspicious MRI regions might be more frequently targeted during cognitive fusion‐targeted biopsy. Two recent studies underline the important message of the present study, and show that a considerable proportion of csPCa is missed in and around MRI‐suspicious lesions by targeted biopsies, as a result of sampling errors related to both misregistration and intra‐tumour heterogeneity [5, 6]. As suggested by these studies, visual guidance by hypoechoic lesions and ‘focal saturation’ biopsy by additional (peri‐)lesional cores might improve the detection of csPCa.
In summary, ‘good old’ TRUS could be of value in those patients who are virtually always present in scenarios in which a grading system is being used, i.e. patients belonging to the so‐called grey zone. The challenge of risk stratification (i.e. personalized medicine) is to nibble at both sides of the grey zone by implementing new techniques or, more likely by implementing a combination of all available and relevant knowledge.
by Monique J. Roobol, Frank-Jan H. Drost and Arnout R. Alberts