Prostate CancerDiagnostic Accuracy of Microultrasound in Patients with a Suspicion of Prostate Cancer at Magnetic Resonance Imaging: A Single-institutional Prospective Study
Introduction
Prostate cancer (PCa) is the most frequently diagnosed cancer among men and the third leading cause of cancer-related mortality [1], [2]. The traditional diagnostic workup of patients suspected for PCa involved prostate-specific antigen (PSA) screening along with transrectal ultrasound (TRUS)-guided biopsy, where 10–12 cores are systematically taken per patient [3]. Unfortunately, this diagnostic pathway is insufficient due to its low sensitivity and specificity, resulting in both overdiagnosis of clinically insignificant PCa and underdiagnosis of clinically significant PCa (csPCa), with at least 28% of patients with an elevated PSA level who have had an initial negative biopsy and who are diagnosed with PCa in a following repeat biopsy [4].
As conventional gray-scale TRUS is not considered by current guidelines as a reliable tool to detect PCa, several imaging techniques enabling targeted biopsies of areas suspicious for malignancy have been investigated [5]. Among these, multiparametric magnetic resonance imaging (MRI) has emerged as an effective tool for the detection of csPCa [6], [7], [8], [9]. Several prospective randomized studies have been reported providing high-level evidence supporting the adoption of an MRI-targeted approach both in the initial and in the repeat biopsy setting [10], [11], [12]. As a consequence, current guidelines recommend the use of MRI-targeted biopsies in these settings [5]. However, the consistent number of csPCa missed by the MRI-targeted biopsy approach still contraindicates the omission of systematic prostate biopsies [8], [13]. In addition, the widespread adoption of MRI has been limited by its availability, increased costs, requirement for radiological expertise, and the complexity related to the MRI-targeted biopsies procedure [14], [15].
Microultrasound (microUS) is a new imaging modality that operates at high frequency (29 MHz), with the resulting microUS images having a resolution of up to 70 μm [16]. Microultrasound uses the Prostate Risk Identification using microUS (PRI-MUS) protocol to characterize and target suspicious regions for PCa, similar to the Prostate Imaging Reporting and Data System (PIRADS) protocol for MRI [17]. The microUS procedure is nearly identical to the standard conventional TRUS, with the additional benefit of enhanced imaging resolution and visualization of suspicious tissue that enables real-time targeted biopsies. The learning curve for microUS for operators already performing TRUS is expected to be short and is limited to simple technique issues and understanding of PRI-MUS characteristics [17]. The aims of the current study were to evaluate the effectiveness of microUS-guided biopsy in the detection of csPCa, defined as a Gleason score of ≥7, and to compare the diagnostic performance of MRI and microUS.
Section snippets
Study population
The study population consisted of 320 consecutive men who were prospectively enrolled at our institution between October 2017 and September 2019. All patients were referred to our center for a suspicion of PCa based on elevated PSA values or abnormal digital rectal examination, and presented with at least one PIRADS ≥ 3 lesion (defined according to the PIRADSv2 protocol) after undergoing prostate multiparametric MRI (mpMRI; performed either with a 1.5-T scanner with an endorectal coil or with a
Study demographics
Table 1 shows patients’ characteristics and stratification according to biopsy setting. The majority of patients had a maximum PIRADS lesion score of 4 (65.3%). Microultrasound identified lesions in 265/320 (79.7%) patients, with the majority having a maximum PRI-MUS score of 4 (49.7%). Significant differences were observed in total PSA, prostate volume, number of biopsy cores taken, and number of positive biopsy cores between patients undergoing first or repeated biopsy. Of the 255 patients
Discussion
In the current prospective study, we evaluated the role of microUS in the detection of csPCa. Our findings showed a similar improvement in csPCa detection by adding microUS targets to that by adding MRI targets. Furthermore, these two modalities appear to provide complementary information that could easily be combined into a single procedure in order to maximize the detection of csPCa.
The role of conventional TRUS in the diagnosis of PCa, at least when only the b-mode imaging is considered, is
Conclusions
Microultrasound demonstrated a considerable potential as a targeted biopsy modality, providing high sensitivity and an acceptable NPV for csPCa. In consequence, microUS may improve the detection rate of csPCa compared with systematic randomized biopsies. In addition, microUS and MRI may be used as complementary imaging techniques, as they appear to provide independent information in a non-negligible proportion of patients.
Author contributions: Giovanni Lughezzani had full access to all the data
References (28)
- et al.
Cancer incidence and mortality patterns in Europe: estimates for 40 countries and 25 major cancers in 2018
Eur J Cancer
(2018) - et al.
Random systematic versus directed ultrasound guided transrectal core biopsies of the prostate
J Urol
(1989) - et al.
Repeat ultrasound guided prostate needle biopsy: use of free-to-total prostate specific antigen ratio in predicting prostatic carcinoma
J Urol
(1998) - et al.
Magnetic resonance imaging-targeted biopsy may enhance the diagnostic accuracy of significant prostate cancer detection compared to standard transrectal ultrasound-guided biopsy: a systematic review and meta-analysis
Eur Urol
(2015) - et al.
Use of prostate systematic and targeted biopsy on the basis of multiparametric MRI in biopsy-naive patients (MRI-FIRST): a prospective, multicentre, paired diagnostic study
Lancet Oncol
(2019) - et al.
Diagnostic accuracy of multi-parametric MRI and TRUS biopsy in prostate cancer (PROMIS): a paired validating confirmatory study
Lancet
(2017) - et al.
Head-to-head comparison of transrectal ultrasound-guided prostate biopsy versus multiparametric prostate resonance imaging with subsequent magnetic resonance-guided biopsy in biopsy-naive men with elevated prostate-specific antigen: a large prospective multicenter clinical study
Eur Urol
(2019) - et al.
What is the negative predictive value of multiparametric magnetic resonance imaging in excluding prostate cancer at biopsy? A systematic review and meta-analysis from the European Association of Urology Prostate Cancer Guidelines Panel
Eur Urol
(2017) - et al.
Diagnostic pathway of patients with a clinical suspicion of prostate cancer: does one size fit all?
Eur Urol
(2018) - et al.
Assessing cancer risk on novel 29 MHz micro-ultrasound images of the prostate: creation of the micro-ultrasound protocol for prostate risk identification
J Urol
(2016)
PI-RADS Prostate Imaging - Reporting and Data System: 2015, version 2
Eur Urol
Comparison of the diagnostic accuracy of micro-ultrasound and magnetic resonance imaging/ultrasound fusion targeted biopsies for the diagnosis of clinically significant prostate cancer
Eur Urol Oncol
Active surveillance magnetic resonance imaging study (ASIST): results of a randomized multicenter prospective trial
Eur Urol
Cancer statistics, 2018
CA Cancer J Clin
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2023, European Urology Open ScienceCitation Excerpt :Despite having nMRI, these patients were referred to our centre for PBx for a persistently high suspicion of PCa based on either clinical (eg, digital rectal examination [DRE]) or laboratory findings. Study design, setting, participants, and overall results have already been reported [11,14]. All patients have provided informed consent before enrolment.