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Performance characteristics of multiparametric-MRI at a non-academic hospital using transperineal template mapping biopsy as a reference standard

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Objectives To evaluate diagnostic accuracy of mpMRI in a non-academic hospital using transperineal template prostate mapping (TPM) biopsy as a reference standard. Secondary objectives included evaluating why mpMRI missed significant cancer. Materials and methods 101 men received pre-biopsy mpMRI and TPM-biopsy over 16 months. Disease status was assigned at hemigland level. Primary histological definition of clinical significance was Gleason grade >/ = 4 + 3 or maximum cancer core length (MCCL) >/ = 6 mm. Positive mpMRI was defined as Prostate Imaging Reporting and Data System (PI-RADS) score >/ = 3. Results Median age 69 (IQR 62–76). Median PSA 7 ng/ml (IQR 4.6–9.8). mpMRI had sensitivity 76.9%, specificity 60.7%, PPV 40.4% and NPV 88.3% at primary definitions. For detecting any Gleason >/ = 7 mpMRI had sensitivity 73.2%, specificity 60.3%, PPV 41.4% and NPV 85.4%. Mean MCCL was lower where significant cancer was missed compared to those correctly identified (5.8 mm versus 7.7 mm respectively, p = 0.035). Conclusion mpMRI performance characteristics were very encouraging when compared to contemporary clinical trials. In a non-academic hospital setting, negative mpMRI was just as good at ruling-out significant disease, though the ability of positive mpMRI to accurately detect significant disease was lower. An mpMRI-guided diagnostic pathway should be accompanied by appropriate mpMRI protocol optimisation, training, and quality control.
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Research Paper
Performance characteristics of multiparametric-MRI at a non-academic hospital
using transperineal template mapping biopsy as a reference standard
Edwin Michael Chau
a
,
b
,
c
, Manit Arya
a
,
b
,
c
, Neophytos Petrides
c
, Zaid Aldin
e
, Jolanta McKenzie
d
,
Mark Emberton
b
, Jaspal Virdi
c
, Hashim Uddin Ahmed
f
,
g
,
1
, Veeru Kasivisvanathan
a
,
b
,
*
,
1
a
Division of Surgery and Interventional Science, University College London, United Kingdom
b
Department of Urology, University College London Hospital, United Kingdom
c
Department of Urology, Princess Alexandra Hospital, United Kingdom
d
Department of Pathology, Princess Alexandra Hospital, United Kingdom
e
Department of Radiology, Princess Alexandra Hospital, United Kingdom
f
Division of Surgery, Department of Surgery and Cancer, Imperial College London, United Kingdom
g
Imperial Urology, Imperial Healthcare NHS Trust, United Kingdom
article info
Article history:
Received 4 January 2018
Accepted 7 January 2018
Available online 31 January 2018
Keywords:
Magnetic resonance imaging
Needle biopsy
Prostatic neoplasm
Predictive value of tests
abstract
Objectives: To evaluate diagnostic accuracy of mpMRI in a non-academic hospital using transperineal
template prostate mapping (TPM) biopsy as a reference standard. Secondary objectives included
evaluating why mpMRI missed signicant cancer.
Materials and methods: 101 men received pre-biopsy mpMRI and TPM-biopsy over 16 months. Disease
status was assigned at hemigland level. Primary histological denition of clinical signicance was
Gleason grade >/¼4þ3 or maximum cancer core length (MCCL) >/¼6 mm. Positive mpMRI was
dened as Prostate Imaging Reporting and Data System (PI-RADS) score >/¼3.
Results: Median age 69 (IQR 62e76). Median PSA 7 ng/ml (IQR 4.6e9.8). mpMRI had sensitivity 76.9%,
specicity 60.7%, PPV 40.4% and NPV 88.3% at primary denitions. For detecting any Gleason >/¼7
mpMRI had sensitivity 73.2%, specicity 60.3%, PPV 41.4% and NPV 85.4%. Mean MCCL was lower where
signicant cancer was missed compared to those correctly identied (5.8 mm versus 7.7 mm respec-
tively, p ¼0.035).
Conclusion: mpMRI performance characteristics were very encouraging when compared to contemporary
clinical trials. In a non-academic hospital setting, nega tivempMRI was just as good at ruling-out signicant
disease, though the ability of positive mpMRI to accurately detect signicant disease was lower. An
mpMRI-guided diagnostic pathway should be accompanied by appropriate mpMRI protocol optimisation,
training, and quality control.
©2018 The Authors. Published by Elsevier Ltd on behalf of Surgical Associates Ltd. This is an open access
article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).
1. Introduction
Transrectal ultrasound (TRUS) guided prostate biopsy is the
standard of care for prostate cancer diagnosis in many countries [1].
It is routinely carried out under local anaesthetic and is relatively
easily learnt, taught and applied, making it a practical diagnostic
strategy. However, it has several recognised limitations and is
prone to random and systematic error [2]. Anterior lesions are
frequently missed, reducing accuracy [3]. Additionally, they can
lead to urosepsis in 1e6% [4].
The use of magnetic resonance imaging (MRI) in the prostate
cancer pathway has seen growing interest due to advances in
technology using a multiparametric approach (mpMRI). This
involves T1 and T2 weighted images (T2W) combined with func-
tional imaging sequences such as diffusion weighted imaging
(DWI) and dynamic contrast enhancement (DCE) [5,6]. If biopsy
could be avoided in men with negative mpMRI then routine use of
pre-biopsy mpMRI could be a cost-effective strategy compared to
TRUS-biopsy [7]. However, as a relatively novel modality, routine
integration of pre-biopsy mpMRI into national diagnostic cancer
pathways has yet to occur.
*Corresponding author. Urology Research Group, Room 4.23, 4th Floor, 132
Hampstead Road, London, NW1 2PT, United Kingdom.
E-mail address: veeru.kasi@ucl.ac.uk (V. Kasivisvanathan).
1
These authors share joint senior authorship.
Contents lists available at ScienceDirect
International Journal of Surgery Open
journal homepage: www.elsevier.com/locate/ijso
https://doi.org/10.1016/j.ijso.2018.01.002
2405-8572/©2018 The Authors. Published by Elsevier Ltd on behalf of Surgical Associates Ltd. This is an open access article under the CC BY-NC-ND license (http://
creativecommons.org/licenses/by-nc-nd/4.0/).
International Journal of Surgery Open 10 (2018) 66e71
Data from experienced academic centres and contemporary
clinical trials show the negative predictive value (NPV) for detec-
tion of signicant cancer for mpMRI ranges from 72 to 92% [8e11 ]
and targeted-only approaches have been shown to detect similar
amounts of signicant cancer to systematic biopsy [12,13].
Randomised studies have shown that MRI performance may be
inuenced by whether the centre was a dedicated high volume
mpMRI academic centre or a non-academic centre, with better
performance of an MRI-guided pathway demonstrated in the aca-
demic centre [14] than outside of one [15]. It is thus known that
optimisation of MRI scanners and the centre's experience has an
important role in mpMRI performance as a diagnostic tool [16].
However, mpMRI has not been validated in non-tertiary referral
(non-academic) centres against a thorough reference standard of
transperineal template mapping biopsy (TPM).
The primary objective of this study was to evaluate the diag-
nostic accuracy of mpMRI in a non-tertiary referral centre using
TPM biopsy as a reference standard. Secondary objectives were to
assess: the additional value of DCE and high b-values on DWI in
detecting cancer and to explore reasons why mpMRI missed
signicant cancer.
2. Material and methods
2.1. Setting
Princess Alexandra Hospital (PAH), a non-academic hospital,
receiving the majority of its referrals for men with suspected
prostate cancer directly from family doctors.
2.2. Patient cohort
All consecutive men who had a TPM biopsy between January 1st,
2015 and April 30th, 2016 were identied from the histopathology
database. The population consisted of a representative cohort of all
men indicated for prostate biopsy including: 1) biopsy naïve men
with suspicion of prostate cancer, 2) men with previous negative
biopsy but continued suspicion of prostate cancer and 3) men with
known low risk prostate cancer conrmed on a previous biopsy on
active surveillance. All men underwent prostate mpMRI and went
on to biopsy regardless of mpMRI ndings. Men were excluded if
the mpMRI was carried out at a different institution or if it
was known in advanced that major MRI artefact would be present
(e.g. pelvic metalwork).
2.3. Transperineal biopsy
TPM biopsy was performed under general anaesthesia using a
modied Barzell technique, reported previously [17].Biopsycores
were taken approximately every 5 mm on the transperineal grid,
aiming for a sampling density of 1 biopsy per ml of tissue. Biopsy
cores were potted separately into one of 12 pots. Where mpMRI
identied a suspicious lesion, additional targeted biopsies were
taken using visual registration technique [12]. One of three experi-
enced surgeons with threeto six years of experience in transperineal
prostate biopsy carried out the procedures.
2.4. Magnetic resonance imaging
mpMRI was performed with one of two scanners (1.5T Siemens
Avanto and 1.5T Siemens Essenza). Sequences included T2W and
DWI imaging for all patients, DCE was introduced after January
2015. Contrast used was 15 ml Dotarem
®
(gadoterate meglumine)
administered at 3 mls/sec (concentration 279.32 mg/ml). All cases
used a pelvic phased array coil without endorectal coils.
mpMRIs were reported by one of three consultant radiologists
with experience in prostate mpMRI ranging from ve to twelve
years. Prostate lesions were scored using ve-level PI-RADS
scale (1ecancer highly unlikely, 2ecancer unlikely, 3eequivocal,
4ecancer likely, 5ecancer highly likely) and scores allocated into 27
sectors. Scoring prior to October 2015 was performed using PI-
RADSv1 [18]. After this, PI-RADSv2 guidelines were adopted [5].
Dedicated high b-values (>/¼1000) were introduced from August
2015. Detailed sequence parameters are shown in Supplementary
Table 1.
2.5. Prostate specimens
Specimens were analysed according to guidelines set by the
Royal College of Pathologists, UK [19].
2.6. Clinical signicance
Our primary objective was based on using the validated UCL
denition 1 (maximum cancer core length [MCCL] >/¼6mmof
any grade or any amount of Gleason grade >/¼4þ3) and PI-RADS
score >/¼3 on mpMRI [10,20]. As there is no accepted universal
denition of clinically signicant cancer results were reported
secondarily according to UCL denition 2 (MCCL >/¼4mmor
Gleason grade >/¼3þ4) and any amount of Gleason grade >/¼7.
2.7. Re-review of mpMRI
False negative (FN) mpMRIs were re-reviewed by a senior
consultant radiologist with pathology results to explore reasons
why the initial report was deemed PI-RADS 1e2. Differences in
characteristics (PSA level, PSA density, gland volume, total cancer
core length (TCCL), and MCCL) between patients with FN and true
positive (TP) mpMRIs were compared to identify features that
might predict missing cancer.
2.8. Analysis
Prostates were analysed on hemigland level as consistent with
previous studies in this eld [10].
Statistical analysis was conducted using Microsoft Excel and
SPSS version 22 (release 22.0.0.0). 2 2 tables to compare presence
or absence of clinically signicant cancer were created. Sensitivity,
specicity, positive predictive value (PPV), NPV, and difference
between proportions with 95% CI were calculated where appro-
priate. Independent T-tests were performed between TP and FN
mpMRI results.
2.9. Ethics
This project was deemed exempt from ethics committee
approval by the research and development department at PAH.
3. Results
3.1. Study population details
122 men were identied who underwent TPM within the study
period. 21 were excluded (1 had mpMRI from another site, 5 had
major artefacts from metalwork, and 15 did not have a pre-biopsy
mpMRI). Median age was 69, median PSA was 7.0 ng/ml and
median prostate volume was 42 ml 24/101 (24%) had no mpMRI
lesion; 76/101 (75%) had a PI-RADS score of >/¼3(Table 1).
Overall detection of all cancer on TPM biopsy was 78/101 (77%).
41/101 (41%) had cancer diagnosed with UCL denition 1; 57/101
E.M. Chau et al. / International Journal of Surgery Open 10 (2018) 66e71 67
(56%) with UCL denition 2; and 43/101 (43%) with any Gleason
>/¼7. Breakdown of cancer detected is given in Table 2.
3.2. mpMRI validity
At primary denitions of clinical signicance, mpMRI achieved
sensitivity 76.9% (95% CI 66e88), specicity 60.7% (95% CI 53e69),
PPV 40.4% (95% CI 31e50) and NPV 88.3% (95% CI 82e95). The
performance characteristics of mpMRI according to varied histo-
logical thresholds for clinically signicant disease is summarised in
Table 3.
3.3. Sub-group analysis: dynamic contrast enhancement
No difference in performance characteristics were shown be-
tween scans with and without DCE (Table 4).
3.4. Subgroup analysis: sequence parameters
46 men had mpMRI scans with dedicated high b-value as part
of the DWI sequences and 55 men had scans prior to use of high
b-values. Addition of high b-values demonstrated a higher speci-
city but lower sensitivity (summarised in Table 5).
3.5. False negative mpMRI
10/12 (83%) hemiglands with signicant cancer (UCL denition
1) missed by mpMRI had lesions located in the apex only and 2/12
(17%) had lesions extending through both apex and base of the
prostate. No missed cancer was found isolated to the base only. 4/12
(33%) lesions were visible on re-review and were missed on initial
reporting (all scoring PI-RADS 1 initially); 6/12 (50%) were difcult
to accurately visualise on re-review due to heterogeneous gland
appearance; 1/12 was not visible at all (8%); and 1/12 (8%) was due
to coding of a midline TPM sector as bilateral disease, therefore no
lesion was actually missed.
The key difference in men who had signicant disease missed by
mpMRIs compared to those who had correctly identied lesions
(Table 6) was mean MCCL, which was signicantly lower in those
cancers missed on mpMRI (means 5.8 mm versus 7.7 mm,
difference 1.9 mm, p ¼0.035).
4. Discussion
4.1. Summary of main ndings
In summary, our study demonstrates that in the context of a
non-academic hospital, mpMRI has good performance character-
istics for the detection of clinically signicant cancer with high
sensitivity 76.9% and NPV 88.3%. This is encouraging for the
adoption of an MRI-inuenced diagnostic pathway outside of
academic centres. As with other studies, specicity 60.7% and PPV
40.4% were low indicating the need for histological verication of a
suspicious area on mpMRI. We also explored possible reasons for
mpMRI missing clinically signicant cancer and showed that when
mpMRI missed cancer, it tended to be low volume disease, with low
maximum cancer core length.
4.2. Clinical implications
mpMRI has been proposed as a triage test for men with sus-
pected prostate cancer, suggesting that men with negative mpMRIs
could avoid biopsy altogether [10,12]. Whilst results seen from the
literature are primarily from tertiary referral centres or clinical trial
settings, there is a distinct lack of results from centres outside these
settings. It is in these pragmatic settings that the validity of
mpMRI needs to be proven to consider widespread adoption of this
strategy as a primary diagnostic approach for suspected cancer.
Table 1
Study population details.
Total number of patients 101
Median age (IQR) 69 (62e76)
Median ml prostate volume (IQR) 42 (30e54)
Median ng/ml PSA (IQR) 7.0 (4.6e9.8)
Median sampling density - number of biopsy cores taken/ml prostate tissue (IQR) 0.94 (0.77e1.3)
Number of mpMRI with contrast enhanced sequences (%) 47 (46.5)
Prior biopsy status (%)
- Previous positive 64 (63.4)
- Previous negative 12 (11.9)
- Biopsy naive 25 (24.8)
MRI result (%)
- PI-RADS score 1 - 2 25 (24.8)
- PI-RADS score 3 32 (31.7)
- PI-RADS score 4 23 (22.8)
- PI-RADS score 5 21 (20.8)
Table 2
Cancer detection results of transperineal template biopsy.
Number of men with clinically signicant cancer (%)
- UCL denition 1 (Gleason grade >/¼4þ3 and/or maximum cancer core length >/¼6 mm) 41 (40.6)
- UCL denition 2 (Gleason grade >/¼3þ4 and/or maximum cancer core length >/¼4 mm) 57 (56.4)
Biopsy result (%)
- Gleason grade 3 þ3 35 (34.7)
- Gleason grade 3 þ4 31 (30.7)
- Gleason grade 4 þ3 6 (5.9)
- Gleason grade 4 þ4 6 (5.9)
- Benign 15 (14.9)
- ASAP or PIN
a
8 (7.9)
a
ASAPeatypical small acinar proliferation, PINeprostatic intraepithelial neoplasia.
E.M. Chau et al. / International Journal of Surgery Open 10 (2018) 66e7168
Our results show that approximately 12% of clinically signicant
cancers (UCL denition 1) would be missed if decisions to avoid
biopsy were based on negative mpMRI alone. The value of a
negative mpMRI is similar to the PROMIS trial which demonstrated
a NPV 89%. The value of a negative mpMRI to rule out signicant
cancer at the less stringent UCL denition 2 is also similar to
PROMIS, with NPV 80%, compared to PROMIS which demonstrated
NPV 72%. These results are very encouraging as they demonstrate
that mpMRI can have good performance characteristics in a prag-
matic setting outside of a tightly regulated clinical trial.
Whilst missing 12e20% (depending on the denition used) of
clinically signicant disease may seem high, one should consider
this in the context of what men would otherwise get. The standard
of care for suspected prostate cancer in many countries is TRUS-
guided biopsy, which commonly has an NPV lower than that seen
for mpMRI in this study, ranging from 36 to 74% for all cancer
detected [11,21e23]. In this context, provided that men with
negative mpMRIs are kept under PSA surveillance it would appear
that mpMRI could have a role in triaging for biopsy. That too,
interpreting a negative MRI in conjunction with a low PSA density
may further help reassure clinicians that avoiding biopsy is safe and
reasonable [24].
However, when comparing the ability of mpMRI to detect
clinically signicant disease (UCL denition 1) and the value of a
positive test result, the results from this study are not as good as
those seen in the PROMIS Trial which demonstrated a sensitivity of
93%. Learning from the re-review of mpMRIs where signicant
cancer was missed, 33% of the FN hemiglands had lesions missed
initially, which were then visible on re-review. This conrms the
known inter-rater variability [25] and might support the concept of
non-suspicious mpMRIs getting a double read if decision about
avoiding biopsy is going to be made.
It should also be emphasised that the current study results
reect an on-going optimisation of mpMRI conduct during the
study period. The PROMIS trial on the other hand had dedicated
quality control of mpMRI conduct and training in mpMRI reporting
built in to the study prior to the commencement of the study. So
perhaps this difference is to be expected. This suggests that in order
to obtain the mpMRI sensitivity seen in contemporary clinical trials,
appropriate quality control, optimisation of protocols and training
is necessary. Results observed in the PROMIS trial cannot be
immediately expected by centres developing an mpMRI service and
a period of optimisation should be expected. Future work should
focus on establishing what this training and quality control should
be and how it should be delivered.
In light of the on-going optimisation of mpMRI conduct during
the study we carried out subgroup analyses to explore the effect
that this had. The use of long-b values in mpMRI has been shown to
improve diagnostic performance and dedicated high-b values are
recommended in PI-RADsv2 [5,26]. The benet of DCE, however, is
not as clear in the literature, with some studies showing no
Table 3
Performance characteristics of multiparametric-MRI in detecting prostate cancer at radiological threshold of PI-RADS score >/¼3 and varied histological thresholds (95% CI
given in parentheses).
Sensitivity Specicity PPV NPV
UCL denition 1 76.9 (66e88) 60.7 (53e69) 40.4 (31e50) 88.3 (82e95)
UCL denition 2 73.1 (63e83) 66.1 (58e75) 57.6 (48e67) 79.6 (72e87)
Gleason grade >/¼3þ4 73.2 (62e85) 60.3 (52e68) 41.4 (32e51) 85.4 (79e92)
Table 4
Performance of multiparametric-MRI with and without contrast in detecting prostate cancer using clinically signicant thresholds of UCL denition 1 and PI-RADS score >/¼3
(95% CI given in parentheses).
Without contrast With contrast Difference between proportions
Sensitivity 86.2 (74e99) 65.2 (46e85) 21 (2e44)
Specicity 60.8 (50e72) 60.6 (49e72) 0.2 (15e16)
PPV 44.6 (32e58) 34.9 (21e49) 9.8 (10e29)
NPV 92.3 (85e100) 84.3 (74e94) 8 (4e20)
Mean age 68.09 69 0.91
Mean PSA, ng/ml 9.01 7.14 1.87
Mean prostate volume, ml 42.9 45.0 2.1
Table 5
Performance of multiparametric-MRI in detecting prostate cancer according to sequence parameters at clinically signicant thresholds of PI-RADS score >/¼3 and UCL
denition 1 (95% CI given in parentheses).
No high b-values High b-values Difference between proportions
Sensitivity 87.1 (75e99) 61.9 (41e83) 25.2 (1.3e49)
Specicity 51.9 (41e63) 70.4 (60e81) 18.5 (3.2e34)
PPV 41.5 (30e54) 38.2 (30e55) 3.3 (17e24)
NPV 91.1 (83e99) 86.2 (77e95) 4.9 (7.3e17)
Mean age 67.3 70 2.7
Mean PSA, ng/ml 8.7 7.5 1.2
Mean prostate volume, ml 45.5 41.9 3.6
Table 6
Comparison between true positive and false negative multiparametric-MRI results
at clinically signicant thresholds of PI-RADS score >/¼3 and UCL denition 1.
True positive False negative Difference
Mean PSA level (ng/ml) 9.4 6.9 2.5 (p ¼0.282)
Mean PSA density (ng/ml/cc) 0.24 0.22 0.02 (p ¼0.694)
Mean Gland volume (cc) 41.7 35.4 6.3 (p ¼0.299)
Mean TCCL (mm) 23.7 11.6 12.1 (p ¼0.152)
Mean MCCL (mm) 7.7 5.8 1.9 (p ¼0.035)
Bold signies signicant result.
E.M. Chau et al. / International Journal of Surgery Open 10 (2018) 66e71 69
advantage [27,28] and others showing that the combination of
sequences improves the performance of the mpMRI [29]. Our data
did not show improved performance of mpMRI with DCE and
whilst the use of high b-values did show higher specicity, in line
with the literature, their use did result in decreased sensitivity.
4.3. Limitations
Radical prostatectomy (RP) specimens would be an alternative
reference standard for diagnostic validity of mpMRI. This however
would be an imperfect reference standard [11] because it could only
be carried out in men who have RP. This would represent selection
bias as one could only assess the validity of mpMRI in men with
high risk features of prostate cancer that are recommended for RP.
Instead, TPM was chosen as the reference standard as it has been
shown to have high diagnostic accuracy and can be applied to all
men at risk of prostate cancer, thus reducing selection bias
[20,30,31]. Furthermore, TPM was carried out at a high sampling
density of almost 1 biopsy per ml of tissue in this study.
We acknowledge that the mpMRI protocols in the study were
modied over time, but this reects continuing development and
optimisation of mpMRI at our centre, which is an essential process
to optimize cancer detection for any centre wishing to adopt
mpMRI. For readers considering adopting their own mpMRI ser-
vices this shows them progressive steps taken. Further, the inu-
ence of changing protocols on the diagnostic performance of
mpMRI was explored and shown to have negligible effect.
5. Conclusion
In conclusion, mpMRI performance characteristics in the
non-academic setting were very encouraging when compared to
contemporary clinical trials. A negative mpMRI was just as good at
ruling-out clinically signicant disease, though the ability of a
positive mpMRI to accurately detect clinically signicant disease
was lower. This supports the adoption of a mpMRI-driven diag-
nostic prostate cancer pathway outside of academic centres,
though this should be accompanied by appropriate mpMRI proto-
col optimisation, training and quality control.
Ethical approval
This project was deemed exempt from ethics committee
approval by the research and development department at PAH.
Funding
Veeru Kasivisvanathan is funded by a Doctoral Research
Fellowship from the National Institute for Health Research. Mark
Embertons research is supported by core funding from the United
Kingdoms National Institute of Health Research (NIHR) UCLH/UCL
Biomedical Research Centre. He was awarded NIHR Senior Inves-
tigator in 2015. The views expressed in this publication are those of
the author(s) and not necessarily those of the NHS, the National
Institute for Health Research or the Department of Health. Hashim
Ahmed receives funding from the Medical Research Council (UK).
Author contribution
Study design: Manit Arya, Zaid Aldin, Veeru Kasivisvanathan,
Jolanta McKenzie.
Data collection: Edwin Michael Chau, Neophytos Petrides, Zaid
Aldin.
Data analysis: Edwin Michael Chau, Veeru Kasivisvanathan.
Writing: Edwin Michael Chau.
Critical revision of manuscript: Manit Arya, Zaid Aldin, Jolanta
McKenzie, Mark Emberton, Jaspal Virdi, Hashim Uddin Ahmed,
Veeru Kasivisvanathan.
Supervision: Manit Arya, Zaid Aldin, Jolanta McKenzie, Mark
Emberton, Jaspal Virdi, Hashim Uddin Ahmed, Veeru Kasivisvanathan.
Obtaining funding: Veeru Kasivisvanathan.
Conicts of interest statement
Hashim Ahmed receives funding from Sonacare Medical,
Sophiris, and Trod Medical for other trials. Travel allowance
was previously provided from Sonacare. Mark Emberton has stock
interest in Nuada Medical Ltd. He is also a consultant to Steba
Biotech and GSK. He receives travel funding from SanoAventis,
Astellas, GSK, and Sonacare. He previously received trial funding or
resources from GSK, Steba Biotech and Angiodynamics and receives
funding for trials from Sonacare Inc, Sophiris Inc, and Trod Medical.
The other authors declare no competing interests.
Guarantor
Veeru Kasivisvanathan.
Edwin Chau.
Research registration number
Research registry 2856.
Appendix A. Supplementary data
Supplementary data related to this article can be found at
https://doi.org/10.1016/j.ijso.2018.01.002.
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... The PRECISION trial also included some non-academic centres and allowed a range of different access routes and registration methods, increasing the generalizability of the findings to other centres 46 . A further study has been carried out in non-academic settings without the dedicated training programme used in PROMIS and a diagnostic performance similar to that seen in the PROMIS trial has been demonstrated (mpMRI sensitivity, PPV and NPV in detecting clinically significant prostate cancer were 73.2%, 41.4% and 85.4%, respectively) 167 . The results of this study are encouraging for the potentially widespread use of mpMRI, as the authors showed that obtaining good diagnostic performance is feasible in a non-academic centre 167 . ...
... A further study has been carried out in non-academic settings without the dedicated training programme used in PROMIS and a diagnostic performance similar to that seen in the PROMIS trial has been demonstrated (mpMRI sensitivity, PPV and NPV in detecting clinically significant prostate cancer were 73.2%, 41.4% and 85.4%, respectively) 167 . The results of this study are encouraging for the potentially widespread use of mpMRI, as the authors showed that obtaining good diagnostic performance is feasible in a non-academic centre 167 . Other issues include the need to increase the capacity to deliver mpMRI, meeting the training needs of clinicians involved and delivering an mpMRI diagnostic pathway within the varying health-care system funding models that currently exist. ...
Article
The current diagnostic pathway for prostate cancer has resulted in overdiagnosis and consequent overtreatment as well as underdiagnosis and missed diagnoses in many men. Multiparametric MRI (mpMRI) of the prostate has been identified as a test that could mitigate these diagnostic errors. The performance of mpMRI can vary depending on the population being studied, the execution of the MRI itself, the experience of the radiologist, whether additional biomarkers are considered and whether mpMRI-targeted biopsy is carried out alone or in addition to systematic biopsy. A number of challenges to implementation remain, such as ensuring high-quality execution and reporting of mpMRI and ensuring that this diagnostic pathway is cost-effective. Nevertheless, emerging clinical trial data support the adoption of this technology as part of the standard of care for the diagnosis of prostate cancer.
Article
Objective To update and externally validate a magnetic resonance imaging (MRI)-based nomogram for predicting prostate biopsy outcomes with a multi-centre cohort. Materials and methods Prospective data from five UK-based centres were analysed. All men were biopsy naïve. Those with missing data, no MRI, or prostate-specific antigen (PSA) > 30 ng/mL were excluded. Logistic regression analysis was used to confirm predictors of prostate cancer outcomes including MRI-PIRADS (Prostate Imaging Reporting and Data System) score, PSA density, and age. Clinically significant disease was defined as International Society of Urological Pathology (ISUP) Grade Group ⩾ 2 (Gleason grade ⩾ 7). Biopsy strategy included transrectal and transperineal approaches. Nomograms were produced using logistic regression analysis results. Results A total of 506 men were included in the analysis with median age 66 (interquartile range (IQR) = 60–69). Median PSA was 6.6 ng/mL (IQR = 4.72–9.26). PIRADS ⩾ 3 was reported in 387 (76.4%). Grade Group ⩾ 2 detection was 227 (44.9%) and 318 (62.8%) for any cancer. Performance of the MRI-based nomogram was an area under curve (AUC) of 0.84 (95% confidence interval (CI) = 0.81–0.88) for Grade Group ⩾ 2% and 0.85 (95% CI = 0.82–0.88) for any prostate cancer. Conclusion We present external validation of a novel MRI-based nomogram in a multi-centre UK-based cohort, showing good discrimination in identifying men at high risk of having clinically significant disease. These findings support this risk calculator use in the prostate biopsy decision-making process. Level of evidence 2c
Article
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Background: Men with high serum prostate specific antigen usually undergo transrectal ultrasound-guided prostate biopsy (TRUS-biopsy). TRUS-biopsy can cause side-effects including bleeding, pain, and infection. Multi-parametric magnetic resonance imaging (MP-MRI) used as a triage test might allow men to avoid unnecessary TRUS-biopsy and improve diagnostic accuracy. Methods: We did this multicentre, paired-cohort, confirmatory study to test diagnostic accuracy of MP-MRI and TRUS-biopsy against a reference test (template prostate mapping biopsy [TPM-biopsy]). Men with prostate-specific antigen concentrations up to 15 ng/mL, with no previous biopsy, underwent 1·5 Tesla MP-MRI followed by both TRUS-biopsy and TPM-biopsy. The conduct and reporting of each test was done blind to other test results. Clinically significant cancer was defined as Gleason score ≥4 + 3 or a maximum cancer core length 6 mm or longer. This study is registered on ClinicalTrials.gov, NCT01292291. Findings: Between May 17, 2012, and November 9, 2015, we enrolled 740 men, 576 of whom underwent 1·5 Tesla MP-MRI followed by both TRUS-biopsy and TPM-biopsy. On TPM-biopsy, 408 (71%) of 576 men had cancer with 230 (40%) of 576 patients clinically significant. For clinically significant cancer, MP-MRI was more sensitive (93%, 95% CI 88-96%) than TRUS-biopsy (48%, 42-55%; p<0·0001) and less specific (41%, 36-46% for MP-MRI vs 96%, 94-98% for TRUS-biopsy; p<0·0001). 44 (5·9%) of 740 patients reported serious adverse events, including 8 cases of sepsis. Interpretation: Using MP-MRI to triage men might allow 27% of patients avoid a primary biopsy and diagnosis of 5% fewer clinically insignificant cancers. If subsequent TRUS-biopsies were directed by MP-MRI findings, up to 18% more cases of clinically significant cancer might be detected compared with the standard pathway of TRUS-biopsy for all. MP-MRI, used as a triage test before first prostate biopsy, could reduce unnecessary biopsies by a quarter. MP-MRI can also reduce over-diagnosis of clinically insignificant prostate cancer and improve detection of clinically significant cancer. Funding: PROMIS is funded by the UK Government Department of Health, National Institute of Health Research-Health Technology Assessment Programme, (Project number 09/22/67). This project is also supported and partly funded by UCLH/UCL Biomedical Research Centre and The Royal Marsden and Institute for Cancer Research Biomedical Research Centre and is coordinated by the Medical Research Council Clinical Trials Unit (MRC CTU) at UCL. It is sponsored by University College London (UCL).
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Background: Routine screening of prostate specific antigen (PSA) is no longer recommended because of a high rate of over-diagnosis of prostate cancer (PCa). Objective: To evaluate the efficacy of diffusion-weighted magnetic resonance imaging (DW-MRI) for PCa detection, and to explore the clinical utility of ultrahigh b-value DW-MRI in predicting prostate biopsy outcomes. Methodology: 73 male patients were selected for the study. They underwent 3T MRI using T2WI conventional DW-MRI with b-value 1000 s/mm2, and ultrahigh b-value DW-MRI with b-values of 2000 s/mm2 and 3000 s/mm2. Two radiologists evaluated individual prostate gland images on a 5-point rating scale using PI-RADS, for the purpose of region-specific comparisons among modalities. Sensitivity, specificity, accuracy, positive predictive value (PPV), negative predictive value (NPV) and likelihood ratios (LR) were investigated for each MRI modality. The area under the receiver operating characteristic (ROC) curve (AUC) was also calculated. Results: Results showed the improved diagnostic value of ultrahigh b-value DWI-MRI for detection of PCa when compared to other b values and conventional MRI protocols. Sensitivity values for 3000 s/mm2 in both peripheral zone (PZ) and transition zone (TZ) were significantly higher than those observed with conventional DW-MRI-Specificity values for 3000 s/mm2 in the TZ were significantly higher than other b-value images, whereas specificity values using 3000 s/mm2 in the PZ were not significantly higher than 2000 s/mm2 images. PPV and NPV between 3000 s/mm2 and the other three modalities were significantly higher for both PZ and TZ images. The PLRs and NLRs of b-value 3000 s/mm2 DW-MRI in the PZ and TZ were also recorded. ROC analysis showed greater AUCs for the b value 3000 s/mm2 DWI than for the other three modalities. Conclusions: DW-MRI with a b-value of 3000 s/mm2 was found to be the most accurate and reliable MRI modality for PCa tumor detection and localization, particularly for TZ lesion discrimination. It may be stated that the b-value of 3000 s/mm2 is a novel, improved diagnostic biomarker with greater predictive accuracy for PCa prior to biopsy.
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Full-text available
To correlate the highest percentage core involvement (HPCI) and corresponding tumor length (CTL), on systematic 12-core biopsy (SBx) and targeted magnetic resonance imaging/transrectal ultrasound (MRI/TRUS) fusion biopsy (TBx), with total MRI prostate cancer (PCa) tumor volume (TV). Fifty patients meeting criteria for active surveillance (AS) based on outside SBx, who underwent 3.0T multiparametric prostate MRI (MP-MRI), followed by SBx and TBx during the same session at our institution were examined. PCa TV's were calculated using MP-MRI and then correlated using bivariate analysis with the HPCI and CTL, for SBx and TBx. For TBx, HPCI and CTL showed a positive correlation (R2 = 0.31, p<0.0001 and R2 = 0.37, p<0.0001 respectively) with total MRI PCa TV, whereas for SBx these parameters showed a poor correlation (R2 = 0.00006, p=0.96 and R2 = 0.0004, p=0.89 respectively). For detection of patients with clinically significant MRI derived tumor burden greater than 500 mm3, SBx was 25% sensitive, 90.9% specific (falsely elevated due to missed tumors and extremely low sensitivity) and 54% accurate in comparison to TBx, which was 53.6% sensitive, 86.4% specific and 68% accurate. HPCI and CTL on TBx positively correlates with total MRI PCa TV, whereas there was no correlation seen with SBx. TBx is superior to SBx for detecting tumor burden greater than 500 mm3. When using biopsy positive MRI derived TV's, TBx better reflects overall disease burden, improving risk stratification amongst candidates for active surveillance.
Article
Purpose: Multiparametric MRI (mpMRI) has an emerging role in prostate cancer (PC) diagnostics. In addition, clinical information are reliable predictors for significant PC (sPC). We analyzed if the negative predictive value (NPV) of mpMRI to rule out sPC could be improved by using clinical factors, especially prostate specific antigen (PSA)-density. Methods: 1040 consecutive men with suspicion of PC underwent mpMRI first, followed by transperineal systematic and MRI/TRUS-fusion-guided biopsy. Logistic regression analyses were performed to test different clinical factors as predictors of sPC and to build nomograms. To simplify these for clinical use, patients were stratified to three PSA-density groups (1: <0.07, 2: 0.07-0.15; 3: >0.15). After stratification, NPVs for PI-RADS Likert score<3 were calculated. sPC was defined as Gleason score (GS)?3+4. High-grade PC was defined as GS?4+3. Results: Overall, 451 men were diagnosed with sPC and 187 had a GS?4+3. In ROC curve analyses the predictive power of the developed nomogram for sPC showed a higher AUC compared to PI-RADS alone (0.79 vs. 0.75, p<0.001). The NPV to harbor sPC increased for men with unsuspicious MRI from 79% up to 89% when these men had a PSA-density ?0.15. In the repeat biopsy setting the NPV for sPC increased from 83% to 93%. The NPV to harbor high-grade PC increased from 92% up to 98% in the entire cohort. Conclusion: Using PSA-density in combination with mpMRI improves the NPV of PI-RADS scoring. By increasing the probability of ruling-out sPC, approximately 20% of unnecessary biopsies could be avoided safely.
Article
Background: An approach based on multiparametric magnetic resonance imaging (mpMRI) might increase the detection rate (DR) of clinically significant prostate cancer (csPCa). Objective: To compare an mpMRI-based pathway with the standard approach for the detection of prostate cancer (PCa) and csPCa. Design, setting, and participants: Between November 2014 and April 2016, 212 biopsy-naïve patients with suspected PCa (prostate specific antigen level ≤15 ng/ml and negative digital rectal examination results) were included in this randomized clinical trial. Patients were randomized into a prebiopsy mpMRI group (arm A, n=107) or a standard biopsy (SB) group (arm B, n=105). Intervention: In arm A, patients with mpMRI evidence of lesions suspected for PCa underwent mpMRI/transrectal ultrasound fusion software-guided targeted biopsy (TB) (n=81). The remaining patients in arm A (n=26) with negative mpMRI results and patients in arm B underwent 12-core SB. Outcomes measurements and statistical analysis: The primary end point was comparison of the DR of PCa and csPCa between the two arms of the study; the secondary end point was comparison of the DR between TB and SB. Results and limitations: The overall DRs were higher in arm A versus arm B for PCa (50.5% vs 29.5%, respectively; p=0.002) and csPCa (43.9% vs 18.1%, respectively; p<0.001). Concerning the biopsy approach, that is, TB in arm A, SB in arm A, and SB in arm B, the overall DRs were significantly different for PCa (60.5% vs 19.2% vs 29.5%, respectively; p<0.001) and for csPCa (56.8% vs 3.8% vs 18.1%, respectively; p<0.001). The reproducibility of the study could have been affected by the single-center nature. Conclusions: A diagnostic pathway based on mpMRI had a higher DR than the standard pathway in both PCa and csPCa. Patient summary: In this randomized trial, a pathway for the diagnosis of prostate cancer based on multiparametric magnetic resonance imaging (mpMRI) was compared with the standard pathway based on random biopsy. The mpMRI-based pathway had better performance than the standard pathway.
Article
Dynamic contrast-enhanced MRI has become a mainstream clinical tool with recognized indications in the imaging of prostate cancer as a part of multiparametric imaging. This technique has successfully moved from research to an easy-to-use routine tool at 1.5T or 3T. Current roles include lesion localization, staging (depiction of capsular penetration and seminal vesicle invasion), and the detection of suspected tumor recurrence following definitive treatment. Limitations of the technique include difficulties in differentiating prostatitis from cancer in the peripheral gland and distinguishing between benign prostatic hyperplasia and transition zone tumors, as well as yet nonstandardized interpretation and reporting techniques. Both may be overcome or attenuated in a near future, by using prostate-dedicated computer-assisted diagnosis software.
Article
Introduction: To assess the accuracy of multiparametric magnetic resonance imaging (mpMRI) for significant PC detection before diagnostic biopsy in men with abnormal PSA/DRE. Material and methods: 388 men underwent mpMRI including T2-weighted, diffusion-weighted & dynamic contrast-enhanced imaging prior to biopsy. Two radiologists used PIRADS reporting system to allocate a score of 1-5 for suspicion of significant PC (Gleason 7 with >5% grade 4). PIRADS score 3-5 was considered positive. Transperineal template-guided mapping biopsy of 18-regions (median 30 cores) were performed, with additional manually directed cores from MRI-positive regions. The anatomical location, size, and grade of individual cancer areas in the 18-biopsy regions, as primary outcome, and in prostatectomy specimens (n=117), as secondary outcome, were correlated to the MRI-positive regions. Results: Of the 388 men that were enrolled, 344 were analyzed. mpMRI was positive in 77.0% of patients, 62.5% had PC and 41.6% had significant PC. Detection of significant PC by mpMRI had sensitivity of 96%, specificity of 36%, NPV and PPV were 92% and 52%. Adding PIRADS to the multivariate model including PSA, DRE, prostate volume and age improved the AUC from 0.776 to 0.879, p<0.001. Anatomical concordance analysis showed a low mismatch between the MRI-positive regions and biopsy-positive regions (n=4(2.9%)), and the significant PC area in RP specimen (n=3(3.3%)). Conclusions: In men with abnormal PSA/DRE, mpMRI detected significant PC with an excellent NPV and moderate PPV. The use of mpMRI for diagnosing significant PC may result in a substantial number of unnecessary biopsies while missing minimum number of significant PC.
Article
The Prostate Imaging - Reporting and Data System Version 2 (PI-RADS™ v2) is the product of an international collaboration of the American College of Radiology (ACR), European Society of Uroradiology (ESUR), and AdMetech Foundation. It is designed to promote global standardization and diminish variation in the acquisition, interpretation, and reporting of prostate multiparametric magnetic resonance imaging (mpMRI) examination, and it is based on the best available evidence and expert consensus opinion. It establishes minimum acceptable technical parameters for prostate mpMRI, simplifies and standardizes terminology and content of reports, and provides assessment categories that summarize levels of suspicion or risk of clinically significant prostate cancer that can be used to assist selection of patients for biopsies and management. It is intended to be used in routine clinical practice and also to facilitate data collection and outcome monitoring for research.
Article
Multiparametric magnetic resonance imaging (MP-MRI) may improve the detection of clinically significant prostate cancer (PCa). To compare MP-MRI transrectal ultrasound (TRUS)-fusion targeted biopsy with routine TRUS-guided random biopsy for overall and clinically significant PCa detection among patients with suspected PCa based on prostate-specific antigen (PSA) values. This institutional review board-approved, single-center, prospective, randomized controlled trial (April 2011 to December 2014) included 130 biopsy-naive patients referred for prostate biopsy based on PSA values (PSA <20 ng/ml or free-to-total PSA ratio ≤0.15 and PSA <10 ng/ml). Patients were randomized 1:1 to the MP-MRI or control group. Patients in the MP-MRI group underwent prebiopsy MP-MRI followed by 10- to 12-core TRUS-guided random biopsy and cognitive MRI/TRUS fusion targeted biopsy. The control group underwent TRUS-guided random biopsy alone. MP-MRI 3-T phased-array surface coil. The primary outcome was the number of patients with biopsy-proven PCa in the MP-MRI and control groups. Secondary outcome measures included the number of positive prostate biopsies and the proportion of clinically significant PCa in the MP-MRI and control groups. Between-group analyses were performed. Overall, 53 and 60 patients were evaluable in the MP-MRI and control groups, respectively. The overall PCa detection rate and the clinically significant cancer detection rate were similar between the MP-MRI and control groups, respectively (64% [34 of 53] vs 57% [34 of 60]; 7.5% difference [95% confidence interval (CI), -10 to 25], p=0.5, and 55% [29 of 53] vs 45% [27 of 60]; 9.7% difference [95% CI, -8.5 to 27], p=0.8). The PCa detection rate was higher than assumed during the planning of this single-center trial. MP-MRI/TRUS-fusion targeted biopsy did not improve PCa detection rate compared with TRUS-guided biopsy alone in patients with suspected PCa based on PSA values. In this randomized clinical trial, additional prostate magnetic resonance imaging (MRI) before prostate biopsy appeared to offer similar diagnostic accuracy compared with routine transrectal ultrasound-guided random biopsy in the diagnosis of prostate cancer. Similar numbers of cancers were detected with and without MRI. ClinicalTrials.gov identifier: NCT01357512. Copyright © 2015 European Association of Urology. Published by Elsevier B.V. All rights reserved.
Article
Multiparametric magnetic resonance imaging (MRI) of the prostate may improve the diagnostic accuracy of prostate cancer detection in MRI-targeted biopsy (MRI-TBx) in comparison to transrectal ultrasound-guided biopsy (TRUS-Bx). Systematic review and meta-analysis of evidence regarding the diagnostic benefits of MRI-TBx versus TRUS-Bx in detection of overall prostate cancer (primary objective) and significant/insignificant prostate cancer (secondary objective). A systematic review of Embase, Medline, Web of Science, Scopus, PubMed, Cinahl, and the Cochrane library was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement. Identified reports were critically appraised according to the Quality Assessment of Diagnostic Accuracy Studies criteria. Only men with a positive MRI were included. The reports we included (16 studies) used both MRI-TBx and TRUS-Bx for prostate cancer detection. A cumulative total of 1926 men with positive MRI were included, with prostate cancer prevalence of 59%. MRI-TBx and TRUS-Bx did not significantly differ in overall prostate cancer detection (sensitivity 0.85, 95% confidence interval [CI] 0.80-0.89, and 0.81, 95% CI 0.70-0.88, respectively). MRI-TBx had a higher rate of detection of significant prostate cancer compared to TRUS-Bx (sensitivity 0.91, 95% CI 0.87-0.94 vs 0.76, 95% CI 0.64-0.84) and a lower rate of detection of insignificant prostate cancer (sensitivity 0.44, 95% CI 0.26-0.64 vs 0.83, 95% confidence interval 0.77-0.87). Subgroup analysis revealed an improvement in significant prostate cancer detection by MRI-TBx in men with previous negative biopsy, rather than in men with initial biopsy (relative sensitivity 1.54, 95% CI 1.05-2.57 vs 1.10, 95% CI 1.00-1.22). Because of underlying methodological flaws of MRI-TBx, the comparison of MRI-TBx and TRUS-Bx needs to be regarded with caution. In men with clinical suspicion of prostate cancer and a subsequent positive MRI, MRI-TBx and TRUS-Bx did not differ in overall prostate cancer detection. However, MRI-TBx had a higher rate of detection of significant prostate cancer and a lower rate of detection of insignificant prostate cancer compared with TRUS-Bx. We reviewed recent advances in magnetic resonance imaging (MRI) for guidance and targeting of prostate biopsy for prostate cancer detection. We found evidence to suggest that MRI-guided targeted biopsy benefits the diagnosis of prostate cancer. Copyright © 2014 European Association of Urology. Published by Elsevier B.V. All rights reserved.