Do patients with a PI-RADS 5 lesion identified on magnetic resonance imaging require systematic biopsy in addition to targeted biopsy?

Introduction: Magnetic Resonance Imaging (MRI)-targeted prostate biopsy (MRI-TB) improves the detection of prostate cancer. These biopsies typically involve both a 12-core systematic biopsy (SB) and MRI-TB of the lesion. Since the majority of PI-RADS 5 lesions represent clinically significant cancers, the utility of SB in addition to MRI-TB is unclear. We evaluate the utility of SB in the setting of PI-RADS 5 lesions in biopsy naïve and active surveillance patients.

Methods: Patients undergoing MRI-TB+SB with a PI-RADS 5 lesion were retrospectively reviewed in a prospectively collected database. Pathology obtained from the MRI-TB was then compared to that of the SB, and each was reported based on the highest Gleason Grade from the sample. In patients with a prior biopsy, we identified instances in which the MRI-TB+SB resulted in upgraded pathology and further subdivided these patients based on whether the pathology upgrade was a result of the TB or the SB.

Results: We identified PI-RADS 5 lesions in 97 patients. All lesions biopsied were found to be prostate cancer, and 86.9% were clinically significant. Gleason Grade from the MRI-TB of the PI-RADS 5 lesions was the same or higher to that of the SB in all but 3 cases (3.1%). Among 59 patients with a prior prostate biopsy, 54 had upgraded pathology from MRI-TB+SB (91.5%). Of these 54 patients, MRI-TB pathology of the PI-RADS 5 lesion was the same or higher to that of the SB in 52 patients (96.3%). In all patients with higher Gleason Grade on SB than MRI-TB, the MRI-TB demonstrated GG3 or higher and SB did not change subsequent clinical management.

Conclusion: In the presence of a PI-RADS 5 lesion, SB offers minimal additional clinical value and could potentially be omitted when performing MRI-TB.