The diagnostic usefulness of magnetic resonance imaging/ultrasound (MRI/US) fusion targeted prostate biopsy is optimized in patients with a PSA level of 5.2 ng/mL or higher, investigators reported in The Journal of Urology (2014;192:1642–1649).

In a prospective study of 1,003 men, researchers led by Peter A. Pinto, MD, of the National Cancer Institute in Bethesda, Md., evaluated the performance of MRI/US targeted biopsy versus 12-core transrectal ultrasound (TRUS)-guided biopsy across a range of PSA values. All patients underwent multiparametric MRI (MP-MRI). Any patient with a lesion suspicious for prostate cancer (PCa) on MP-MRI underwent standard 12-core TRUS-guided biopsy.

Of the 1,003 patients, 564 were diagnosed with PCa, for a 56.2% detection rate. Targeted biopsy led to significantly more upgrading to clinically significant cancer compared with 12-core biopsy.

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This trend increased more with increasing PSA, specifically in patients with PSA values of 4 to 10 ng/mL, the researchers stated. PSA levels of 5.2 ng/mL or higher captured 90% of upgrading by targeted biopsy. At this cutoff, the researchers reported, 36% of the total cohort would have been spared targeted biopsy or possibly even re-imaging.

Using an optimized threshold, targeted biopsy, and by extension MP-MRI, may not be necessary below a PSA level of 5.2 ng/mL, the authors concluded.

The researchers noted that a limitation of their study was that, for most patients, the final prostatectomy specimen pathology was not available, so verifying the actual disease burden was not possible.