Results of Targeted Biopsy in Men with Magnetic Resonance Imaging Lesions Classified Equivocal, Likely or Highly Likely to Be Clinically Significant Prostate Cancer

Background: The Prostate Imaging Reporting and Data System (PI-RADS) is the most commonly used scoring system in prostate magnetic resonance imaging (MRI). One of the available techniques to target suspicious lesions is direct in-bore MRI-guided biopsy (MRGB).

Objective: To report on the experience and results of MRGB in a large cohort of patients with lesions classified as equivocal (PI-RADS 3), likely (PI-RADS 4), or highly likely (PI-RADS 5) to be clinically significant (cs) prostate cancer (PCa).

Design, setting, and participants: We retrospectively included 1057 patients having MRGB, between January 2012 and September 2016, of lesions classified as PI-RADS≥3 on multiparametric MRI. Biopsy-naïve patients, patients with prior negative systematic transrectal ultrasound-guided biopsy, and patients in active surveillance were included.

Outcome measurements and statistical analysis: The primary outcome measurement is the detection rate of csPCa. Descriptive statistics and chi-square tests were used to calculate the differences in proportions. We considered a Gleason score of ≥3+4 as csPCa.

Results and limitations: PCa was diagnosed in 35% (55/156), 60% (223/373), and 91% (479/528), and csPCa in 17% (26/156), 34% (128/373), and 67% (352/528) of patients with PI-RADS 3, 4, and 5 lesions, respectively. Follow-up of patients with negative biopsy findings resulted in csPCa in 1.7% (5/300) after a median period of 41 (interquartile range 25-50) mo. The evaluation of prostate-specific antigen density (PSAD) to predict csPCa resulted in 42% of patients with a PI-RADS 3 lesion who could avoid biopsy in case a PSAD of ≥ 0.15ng/ml/ml would be used. In 6% (95% confidence interval, 2-15), csPCa would then be missed. The study is limited because of its retrospective character.

Conclusions: MRGB in lesions scored PI-RADS≥3 yields high detection rates of csPCa in daily clinical practice in cases with previous negative biopsy.

Patient summary: In daily clinical practice, direct in-bore magnetic resonance imaging-guided biopsy of suspicious lesions reported according to the Prostate Imaging Reporting and Data System yields high detection rates of clinically significant prostate cancer.