MRI-targeted prostate biopsy offers four fundamental benefits

Magnetic resonance imaging (MRI) is a promising tool for optimizing prostate cancer biopsy that appears to overcome the shortcomings of conventional systematic transrectal ultrasound (TRUS)-guided biopsy and also provides novel information for risk stratification that can guide the decision of whether to perform biopsy, according to Samir Taneja, MD.

Speaking at the Large Urology Group Practice Association annual meeting in Chicago, Dr. Taneja, of the NYU Langone Medical Center in New York, reviewed findings from studies conducted at his center evaluating MRI as a tool for guiding biopsy and biopsy decisions. The research included analyses of data collected in the first 605 men who underwent MRI-targeted biopsy and also a standard systematic 12-core biopsy.

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Based on the results, Dr. Taneja proposed that MRI appears to offer four fundamental benefits.

First, in men who have never been biopsied before, an MRI-targeted approach appears to maintain similar rates of detection of clinically significant, high-grade cancer compared to standard TRUS-guided biopsy while reducing detection of clinically insignificant, low-grade cancer.

“Therefore, MRI-targeted biopsy in this population could reduce the problem of cancer over-detection and overtreatment,” said Dr. Taneja.

Second, in men with a previous negative biopsy, an MRI-targeted approach appears to allow increased detection of cancer and increased detection of high-grade cancer versus standard TRUS-guided biopsy.

“Not surprisingly, standard systematic biopsy is rarely informative in these men who had already had negative results with that technique, and our data suggest that such patients would not need to undergo a 12-core biopsy at all,” Dr. Taneja said.

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More accurate identification of high-grade disease

Third, in men with biopsy-confirmed low-grade cancer undergoing active surveillance, MRI-targeted biopsy allowed accurate identification of high-grade disease, but could do so with less sampling.

Finally, use of a 5-point scoring system, validated at the NYU Langone Medical Center, to interpret the MRI showed promise for guiding selection of men who do and do not need biopsy. Dr. Taneja reported that the MRI suspicion score, which ranges from 1 (normal) to 5 (most suspicious), correlated well with the likelihood of finding high-grade disease on biopsy, while there was no correlation between the MRI suspicion score and the finding of low-grade disease.

“We think that in the future, we may be able to use the suspicion score in combination with other features to help us decide whether or not a man should even undergo biopsy,” Dr. Taneja said.

“For example, in a 75-year-old man with an elevated PSA who likely has prostate cancer based on his age, we might choose not to perform biopsy if his MRI suspicion score is 2 or 3 because he would be unlikely to have high-grade cancer that would be an indication for treatment. However, a 55-year-old man with the same MRI findings may choose to have the biopsy, as he may choose to be treated for earlier stages of disease.”

Dr. Taneja said that, at NYU, an ultrasound-guided approach to MRI-targeted biopsy is being used rather than MRI-guided biopsy, which is performed by a radiologist with the patient in the MRI scanner. Based on findings of his recently published prospective study comparing MRI-ultrasound fusion biopsy and visual estimation, Dr. Taneja said that the fusion technique is now the standard approach for MRI-targeted prostate biopsy at NYU.

“In our study, the fusion approach did not increase cancer detection. However, it was associated with identification of more cancer in each core and was, therefore, more informative. In addition, there was an indication that the fusion approach allowed more accurate tumor targeting in general and of tumors that are in difficult locations within the prostate,” he said.

The study findings “support the concepts that MRI-targeted biopsy enables better risk stratification and can minimize the need for repeat biopsies or the number of samples needed in repeat biopsy,” Dr. Taneja concluded.

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