Transperineal Multiparametric MRI-Ultrasound Fusion Targeted Prostate Biopsy Combined with Standard Template Improves Prostate Cancer Detection

David Ambinder MD.

With the increasing popularity of transperineal prostate biopsies over transrectal ultrasound (TRUS) guided biopsies, due to lower risks of complications and similar or superior prostate cancer detection rates, the introduction of software-based targeting of lesions on multiparametric magnetic resonance imaging (mpMRI) has further improved the accuracy of prostate cancer detection. However, the question that has remained to be convincingly answered is whether there is “added value” in using a targeted approach compared with the standard template alone, or whether using both should be preferred for performing transperineal fusion targeted biopsies.

A step closer to the definitive answer to this question has been achieved by a study by researchers at Massachusetts General Hospital, Harvard Medical School, Boston, led by Douglas M. Dahl, MD, Chief of the Division of Urologic Oncology.1 The group compared detection rates of overall and clinically significant prostate cancer using MRI fusion targeted versus standard template biopsies in 301 patients that underwent in-office transperineal prostate biopsy at Massachusetts General Hospital between 2019 and 2021. All patients had ≥1 lesion(s) on prostate mpMRI prior to biopsy.

mpMRI was performed using a Discovery 3.0 T MR750 system (GE Healthcare) without an endorectal coil. All biopsies were performed using the transperineal template and the PrecisionPoint Transperineal Access System (Perineologic) under local anesthesia. All patients had 3-4 targeted biopsy cores followed by concomitant standard template biopsies.  Systematic, non-targeted biopsy cores were obtained with 2 cores at different locations taken from each of 10 sites bilaterally. A median of 20 template cores and 3 targeted cores was obtained per prostate.

The overall cancer detection rate of the template plus targeted biopsy was 79.1% patients, 62.2% of which were found to be clinically significant prostate cancer. The cancer detection rate for the template biopsy alone was significantly higher than for the targeted biopsy (74.1% vs 63.5%, P<0.001). There was no significant difference between the two approaches in detection of clinically significant prostate cancer (52.5% vs 59.7%, respectively).

A total of 176 (58.5%) of the 301 patients were positive for prostate cancer on both the standard template and targeted biopsies, of which 111 (63%) were of similar Gleason score on both samples. Cases upgraded included 33 (18.8%) on targeted biopsy and 32 (18.2%) on template biopsy. For clinically significant disease, 35.2% were upgraded on targeted biopsy and 32.4% on template biopsy. Of 78 cases with benign disease on template biopsy, 19.2% were upgraded on target biopsy to prostate cancer and 7.7% to clinically significant disease, whereas of the 110 patients who had benign targeted biopsies, 42.7% were upgraded to prostate cancer, of which 10.9% were found to have clinically significant disease. The combined approach detected 20.6% (62/301) of cases that would have been missed using either targeted or template biopsy alone.

Dr Dahl and his colleagues point out that their findings, especially that of 18.2%, missed clinically significant prostate cancer cases in targeted biopsies, are in-line with previous studies comparing transrectal and transperineal template biopsy by their group and others at different institutions.2-4  Their findings support the use of a combined approach with both a standard template as well as a mpMRI targeted biopsy when available and possible, since their study showed that the two methods were complementary. Targeted biopsies identified overall prostate cancer in 19.2% of negative template biopsies and avoided 28.6% of clinically significant prostate cancer diagnoses, consistent with previous studies.5,6

They also acknowledge that one limitation of the study, aside from its retrospective and nonrandomized nature, was the lack of final prostatectomy pathology, which would usually be the endpoint for determining future treatment. The researchers reveal that they are planning a study to compare template and targeted biopsies with radical prostatectomy and treatment outcomes. Finally, they caution that their study did not evaluate safety or patient satisfaction.

In the first of two editorial comments published alongside the study, Jun C. Hu, MD and colleagues at Weill Cornell Medical College, New York, point out that high cost is “a significant barrier” to widespread adoption of transperineal in-office biopsy using the PrecisionPoint device, which is single-use and costs around $200, an expense that is not currently recoverable, they add. This may account for the current low rate of in-office transperineal biopsies at less than 5% of all biopsy approaches, they imply. In addition, they note that in this study, more noninfectious complications were seen with the transperineal over the transrectal biopsies. They call for more studies to determine whether these are secondary to the transperineal approach or due to the greater number of cores used compared with the transrectal approach.

In the second editorial comment, Shu Wang, MD, and M. Minhaj Siddiqui, MD, from the University of Maryland School of Medicine, Baltimore, also point out that the study involved 23 core biopsies per patient compared with 12-core standard transrectal biopsy templates.  Investigations are needed to identify more efficient templates, they say, so that increased diagnostic accuracy can be achieved with decreased morbidity from the prostate biopsy.

David Ambinder, MD is a urology resident at New York Medical College / Westchester Medical Center. His interests include surgical education, GU oncology and advancements in technology in urology. A significant portion of his research has been focused on litigation in urology.  

References

  1. Kim MM, Wu S, Lin SX, et al. Transperineal multiparametric magnetic resonance imaging-ultrasound fusion targeted prostate biopsy combined with standard template improves prostate cancer detection. J Urol. 2022;207(1):86-94. DOI: 1097/JU.0000000000002168
  2. Hanna N, Wszolek MF, Mojtahed A, et al. Multiparametric magnetic resonance imaging-ultrasound fusion biopsy improves but does not replace standard template biopsy for the detection of prostate cancer. J Urol. 2019;202(5):944-951. DOI: 1097/JU.0000000000000359
  3. Siddiqui MM, Rais-Bahrami S, Truong H, et al. Magnetic resonance imaging/ultrasound-fusion biopsy significantly upgrades prostate cancer versus systematic 12-core transrectal ultrasound biopsy. Eur Urol. 2013 ;64(5) :713-719. DOI : 1016/j.eururo.2013.05.059
  4. Tewes S, Peters I, Tiemeyer A, et al. Evaluation of MRI/ultrasound fusion-guided prostate biopsy using transrectal and transperineal approaches. Biomed Res Int. 2017; 2017:2176471. DOI: 1155/2017/2176471
  5. Kasivisvanathan V, Dufour R, Moore CM, et al. Transperineal magnetic resonance image targeted prostate biopsy versus transperineal template prostate biopsy in the detection of clinically significant prostate cancer. J Urol. 2013;189(3):860-866. DOI: 1016/j.juro.2012.10.009
  6. Radtke JP, Kuru TH, Boxler S, et al. Comparative analysis of transperineal template saturation prostate biopsy versus magnetic resonance imaging targeted biopsy with magnetic resonance imaging-ultrasound fusion guidance. J Urol. 2015;193(1):87-94. DOI: 1016/j.juro.2014.07.098