Fusion-Guided Biopsy Improves Prostate Cancer Detection

Fran Lowry

June 04, 2014

Combining MRI with ultrasound to guide prostate biopsy in men suspected of having prostate cancer can enhance the detection of clinically significant cancers, according to the results of a phase 3 clinical trial published in the Journal of Urology.

The good results with an MRI/transrectal ultrasound (TRUS) fusion–guided prostate biopsy system echo those originally seen in studies conducted at the National Institutes of Health, which is where the technology was first used, lead author, Ardeshi R. Rastinehad, MD, from Hofstra North Shore-Jewish School of Medicine, New Hyde Park, New York, told Medscape Medical News.

Dr. Rastinehad and his group used a commercially available system called UroNav (Invivo) to evaluate its ability to detect cancer, as well as its feasibility for use in a community setting.

"This technology is trying to overcome the inherent limitations associated with an ultrasound-only approach," Dr. Rastinehad said. "The MRI allows us to evaluate men with suspicious lesions, and when they do have them, we are able to actually target those lesions and make the diagnosis."

 
The fusion-guided technique is like a GPS for cancer. Dr. Ardeshi R. Rastinehad
 

The "exciting thing" he added, "is no longer do we just use ultrasound to guide biopsy of the various regions, we're actually able to target specific areas with the prostate to help make the diagnosis of clinically significant prostate cancer. The fusion-guided technique is like a GPS for cancer," he said.

Phase 3 of the New System

Their study included 105 men who were enrolled between 2012 and 2013. Their mean age was 65.8 years and mean prostate specific antigen was 9.5 ng/mL.

The men underwent 3-Tesla multiparametric MRI with an endorectal coil for clinical suspicion of prostate cancer. Lesions thus identified were classified as low or moderate/high risk for prostate cancer.

The men underwent both MRI/transrectal ultrasound fusion–guided biopsy and standard 12-core prostate biopsy.

Overall, cancer was detected in 62.9% of the men.

The cancer detection rate in men with moderate or high risk on imaging was 72.3% (47 of 65) vs 47.5% (19 of 40) in those classified as low risk for prostate cancer (P < 0.05).

The mean tumor core lengths were 4.6 mm for fusion biopsy and it was 3.7 mm (P < 0.05).

MRI/TRUS fusion–guided biopsy detected prostate cancer that was missed by standard 12-core biopsy in 14.3% of cases (15 of 105), and of these cases, 86.7% (13 of 15) were clinically significant.

"This biopsy upgraded 23.5% of cancers (4 of 17) deemed clinically insignificant on 12-core biopsy to clinically significant prostate cancer necessitating treatment," Dr. Rastinehad said.

The technology comes with a bit of a learning curve, but the biggest factor in its success is the quality of the imaging, he added.

"The better your imaging is, the better your interpretation and the better able you are to hit meaningful targets, so it's a key collaboration between radiology and urology to make this technology work," he said.

He added that the fusion technology does not do as good a job detecting low-grade, low-volume prostate cancer. But, he said, "that is OK, we don't want to find all prostate cancers because of over-diagnosis and over-treatment. The technology helps us find a more select group and our study is the first to validate the work from the NIH. We are excited that we are able to reproduce the results from their studies."

A trial comparing traditional ultrasound guided biopsy with MRI-guided biopsy was presented earlier this year in Stockholm, Sweden, at the European Association of Urology 29th Annual Congress.

The results from that trial were similarly encouraging. Morgan Pokorny, MD, a urologist from the Wesley Hospital in Brisbane, Australia, who presented the data from the trial, announced that "MRI has now become the investigation of choice for all men with suspected prostate cancer; it has completely radicalized and changed our paradigm."

He added "One of the key messages is that urologists and radiologists need to become best friends."

And, in an interview with Medscape Medical News, Dr. Pokorny said, "I think the future lies with MRI. We're not categorically saying you shouldn't do TRUS-guided biopsies, but we think that MRI can help you risk-stratify very powerfully — more so than any other tool."

Reassuring Data

In an editorial accompanying the latest study, Boris A. Hadaschik, MD, and Timur H. Kuru, MD, from the University of Heidelberg, Germany, write that the current study "adds reassuring data to the literature on MRI targeted prostate biopsy," and also that it "demonstrates that fusion-guided prostate biopsy can easily be transferred from a research institution to a dedicated community-based practice setting."

Drs. Hadaschik and Kuru also write that image-guided prostate biopsy improves detection of clinically significant cancer, but an important question remains, and that is whether targeted biopsies alone or in addition to a systematic regimen are optimal for primary or repeat biopsies.

Another comment accompanying the article, by J. Stephen Jones, MD, from Cleveland Clinic Regional Hospital System in Ohio, stated that the new technology missed cancers that were more likely to be clinically insignificant.

"We should aspire to forego identification of these tumors to avoid the stress, cost and potential risk of overtreatment and over diagnosis. If MRI can eventually identify only significant cancers reliably and obviate the need for us to pass needles through insignificant findings, the field of CaP [prostate cancer] diagnostics will take a quantum leap forward."

Dr. Rastine has no financial agreements with Invivo, the manufacturer of the UroNav system, and or in the outcome of the study but states that UroNav provided the equipment as part of a research agreement with his institution. Dr. Pokorny, Dr. Hdaschik, Dr. Kuru, and Dr. Jones have disclosed no relevant financial relationships.

J Urol. 2014;191:1749-1754. Abstract Hadaschik and Kuru Editorial Jones Editorial

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