Two recent studies provide evidence that fusion-guided biopsy—a combination of MRI and real-time ultrasound—is superior to standard 12-core ultrasound biopsy for detecting and grading prostate cancer.
In the first study,1 researchers from Long Island Jewish Medical Center and the National Institutes of Health studied 105 men who had elevated prostate-specific antigen (PSA), abnormal digital rectal examination, and MRI-detected suspicious lesions in the prostate. The subjects first underwent a prostate biopsy using the UroNav system (InVivo, Gainesville, FL), which fuses MRI and transrectal ultrasound (TRUS) so as to target the biopsy needles to suspicious areas of the prostate. Subjects then underwent standard 12-core TRUS-guided biopsy.
The researchers found that 28% more cases of clinically significant prostate cancer were detected by fusion-guided biopsy compared with standard TRUS-guided biopsy.
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Fusion-guided biopsy detected 15 cancers in the 105 subjects that standard biopsy missed, of which 12 were clinically significant. In addition, 4 of 17 cancers regarded on standard biopsy as low-risk disease were determined by fusion-guided biopsy to be clinically significant disease requiring treatment.
“The results of this phase 3 clinical trial show that target fusion biopsy detects more clinically significant prostate cancer,” said Art Rastinehad, DO, the study’s principal investigator. “This is the type of cancer that patients may benefit from treating compared with other patients with low-grade and low-volume prostate cancer.”
Criteria for Active Surveillance Questioned
On the opposite coast, researchers at the University of California, Los Angeles used the Artemis MRI/US fusion device (Eigen, Grass Valley, CA) to determine whether men presumed to have low-risk prostate cancer actually had higher-risk disease.2
The researchers studied 113 men who were enrolled in an active surveillance program for prostate cancer. All had previously undergone standard TRUS-guided biopsy, which had not found aggressive cancer.
The subjects then underwent fusion-guided biopsy. “Prostate cancer is difficult to image because of the limited contrast between normal and malignant tissues within the prostate,” said Leonard Marks, MD, who led the research team. “With the Artemis, we have a virtual map of the suspicious areas placed directly onto the ultrasound image during the biopsy. When you can see a lesion, you’ve got a major advantage of knowing what’s really going on in the prostate.”
Fusion-guided biopsy demonstrated that 41 of the 113 subjects had more aggressive cancer than initially suspected and needed treatment.
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“These findings are important as active surveillance is a growing trend in this country,” Dr. Marks said. “It’s an excellent option for many men thought to have slow-growing cancers. But we show here that some men thought to be candidates for active surveillance based on conventional biopsies really are not good candidates.”
The researchers now recommend that criteria for active surveillance of prostate cancer be re-evaluated. “We are hesitant now to enroll men in active surveillance until they undergo targeted biopsy,” Marks said. “Fusion biopsy will tell us with much greater accuracy than conventional biopsy whether or not they have aggressive disease.”
- Rastinehad AR, Turkbey B, Salami SS, et al. Improving detection of clinically significant prostate cancer: magnetic resonance imaging/transrectal ultrasound fusion guided prostate biopsy. J Urol. 2014;191(6):1749-1754.
- Hu JC, Chang E, Natarajan S, et al. Targeted prostate biopsy to select men for active surveillance: do the Epstein criteria still apply? J Urol. 2014 Feb 8. pii: S0022-5347(14)00250-X. doi: 10.1016/j.juro.2014.02.005. [Epub ahead of print]