MRI-ultrasound Fusion and Transrectal Ultrasound-guided Prostate Biopsy in Patients with Prior Negative Biopsies: Diagnostic Accuracy of Significant Prostate Cancer Detection in a multicenter series

Alessanro Giacobbe1, Rocco Papalia2, Emanuela Altobelli2, Leonardo D'Urso1, Andrea Formiconi1, Rodolfo Rosso1, Gian Luca Muto2, Devis Collura1, Emanuele Castelli1, Giovanni Muto2
  • 1 Ospedale San Giovanni Bosco, S.C. Urologia (Torino)
  • 2 Università Campus Bio-Medico, U.O.C. Urologia (Roma)

Objective

An extended Prostate Biopsy (10–12 cores) remains the standard for the initial diagnostic evaluation of a suspicious prostate1.The rate of prostate cancer (PCa) detection for a first systematic transrectal ultrasound-guided biopsy (TRUS-GB) is typically 30–50%2. Nevertheless, clinically significant PCa can be missed even after several repeat TRUS-GB. This applies especially to patients with anteriorly located tumors, which are frequently underdiagnosed by TRUS-GB3. Multiparametric MRI of the prostate is able to detect clinically relevant CaP4. The ability to visualize some PCa on MRI has brought the opportunity to use those images as targets for needle biopsy by incorporating (i.e. fusing) MRI into a needle-aiming or targeting method5.
The aim of the study was to evaluate the accuracy of targeted magnetic resonance imaging (MRI)-ultrasound fusion–guided biopsy (FUS-GB) in the diagnosis of clinically significant prostate cancer (PCa) and to compare PCa detection between FUS-GB alone and FUS-GB + TRUS-GB in patients with prion negative biopsies for cancer.

Materials and Methods

Between February 2014 and January 2016, we consecutively included in the study all men who underwent multiparametric MRI and then MRI/US fusion biopsy with previous history of negative prostate biopsy and a PSA level of 4-20 ng/mL. Overall, 223 men were included in this study, enrolled in 3 centers: Dept of Urology Hospital San Giovanni Bosco of Turin – Clinica Fornaca of Turin – Dept of Urology Campus Bio Medico of Rome. All men underwent a 12 extended-cores protocol plus 2-3 targeted cores on the multiparametric MRI (mpMRI) index lesion. The UroStation™ (Koelis, France) and a V10 ultrasound system with an end-fire 3D TRUS transducer were used for the fusion images procedure.

Results

The mean patient age was 67 (48-77) years old, the mean PSA level at biopsy was 9.4 (2.3-20) ng/mL. pathologic report of previous biopsies were : 145 BPH, 40 phlogosis, 12 PIN hg, 26 ASAP. 123/223 patients (55.1%) had positive biopsies with Gleason score 3+3 in 63 patients (51%), Gleason score 3+4 or 4+3 in 48 patients (39%), Gleason score 4+4 in 12 patients (10%). MRIdetected at least 1 suspicious area in 160 patients (72%), 2 or more suspicious area in 63 patients (28%). The median time between MRI and biopsy was 30 days. The number of men diagnosed with clinically significant cancer was 36 (29%) with TRUS-GB and 59 (48,3%) with FUS-GB.

Discussions

Three methods of MRI guidance are available for targeted prostate biopsy: cognitive fusion, ; direct MRI-guided biopsy, performed within an MRI tube; and software coregistration of stored MRI with realtime ultrasound, using a fusion device6.
In FUS-GB, the operator images the prostate using ultrasound, as performed for the past several decades; while thus viewing the prostate, the MRI of that prostate, which is performed beforehand and stored in the device, is fused with real-time ultrasound using a digital overlay, allowing the target(s), previously delineated by a radiologist, to be brought into the aiming mechanism of the ultrasound machine. our registration system uses an elastic (deformable) image registration that is performed with a 3D TRUS probe to acquire prostatic volume. Before each biopsy 3D TRUS acquisition is performed to calculate the deformation of the prostate shape on MR images. Thus, it is not a real-time technique but the spatial accuracy of the system after image registration was reported to be close to 1 mm. In our study, target biopsy with computerized MRI-TRUS image registration significantly improved cancer detection over that of systematic transrectal ultrasound-guided biopsy.This improvement was for both the clinically significant cancers that for clinically insignificant cancers. FUS-GB alone missed only 2 high grade cancers detected by TRUS-GB.

Conclusion

In our experience, MRI–ultrasound fusion for lesion targeting is likely to result in fewer and more accurate prostate biopsies than the current use of systematic biopsies with ultrasound guidance alone.
MRI-ultrasound fusion–guided biopsy detected more men with clinically significant PCa thansystematic transrectal ultrasound-guided biopsy. The limit of this method is that it is indirect, involves use of an additional device and requires specialized operator training. The advantage is that it can be performed within minutes in an outpatient clinic setting under local anaesthesia, using techniques familiar for several decades. Results using a fusion device are very promising. Targeted biopsy has the potential to reduce overdiagnosis. Randomized extended and saturation prostate biopsy have dominated the prostate biopsy scenario in the past, they are still the gold standard, but probably they do not represent the future

References

1. Eichler K, Hempel S, Wilby J, et al. Diagnostic value of systematic biopsy methods in the investigation of prostate cancer: a systematic review. J Urol 2006 May;175(5):1605-12.
2. Cormio L, Scattoni V, Lorusso F, et al. Prostate cancer detection rates in different biopsy schemes. Which cores for which patients? World J Urol 2014;32:341–6.
3. Komai Y, Numao N, Yoshida S, et al. High diagnostic ability of multiparametric magnetic resonance imaging to detect anterior prostate cancer missed by transrectal 12-core biopsy. J Urol 2013; 190:867–73
4. Barentsz JO, Richenberg J, Clements R, et al. ESUR prostate MR guidelines 2012. Eur Radiol. 2012; 22:746–757. [PubMed: 22322308] . Current clinical guidelines for multiparametric prostate MRI.
5. Moore CM, Robertson NL, Arsanious N, et al. Image-guided prostate biopsy using magnetic resonance imaging-derived targets: a systematic review. Eur Urol. 2012.
6. Leonard Marksa, Shelena Young, and Shyam Natarajan. MRI–ultrasound fusion for guidance of targeted prostate biopsy. Current opinion Volume 23 _ Number 1 _ January 2013

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