Are Magnetic Resonance Imaging-Transrectal Ultrasound Guided Targeted Biopsies Noninferior to Transrectal Ultrasound Guided Systematic Biopsies for the Detection of Prostate Cancer?

PURPOSE

In men with suspicion of prostate cancer the standard of cancer detection is transrectal ultrasound guided 10 to 12-core systematic biopsy. The targeted biopsy only strategy using magnetic resonance imaging-transrectal ultrasound image registration is gaining in popularity. We assessed the noninferiority of targeted vs systematic biopsy.

MATERIALS AND METHODS

Between June and October 2014 a total of 108 biopsy naïve patients with prostate specific antigen between 4 and 20 ng/ml, normal rectal examination and a single suspicious image on magnetic resonance imaging were included in study at 7 centers. Patients underwent systematic biopsy by a first operator blinded to magnetic resonance imaging, immediately followed by 3 targeted biopsies within the suspicious image by a second operator. The primary end point was the cancer detection rate. The noninferiority margin was set at -5%. The secondary end points were the detection rate of clinically significant prostate cancer (maximum cancer core length 5 mm or greater for Gleason 6 or any Gleason 7 or greater disease) and procedure duration.

RESULTS

Systematic and targeted biopsies detected cancer in 66 (61.1%) and 61 patients (56.5%), respectively. The mean difference was -4.5% with a 95% CI lower bound of -11.8%. A total of 13 patients with protocol violations were excluded from the per protocol analysis, which showed a mean difference of -5.2% with a 95% CI lower bound of -13.1%. Clinically significant prostate cancer was detected in 50 (46.2%) and 52 patients (48.1%) with systematic and targeted biopsies, respectively (p = 0.69). The mean ± SD duration of image fusion plus targeted biopsy was 16.7 ± 7 minutes vs 7.4 ± 3 for systematic biopsy (p <0.001).

CONCLUSIONS

Targeted biopsy seemed to be inferior to systematic biopsy for overall cancer detection. Detection of clinically significant prostate cancer did not differ between targeted and systematic biopsies.