[Prebiopsy multiparametric MRI of the prostate: the end of randomized biopsies?].

OBJECTIVE

To evaluate the value of multiparametric MRI-targeted prostate biopsies in patients with suspected low-risk prostate cancer.

PATIENTS AND METHOD

Patients with normal digital rectal examination and a PSA level between 4 and 10 ng/mL were prospectively included. A multiparametric MRI of the prostate was performed prospectively before the biopsies. 12-core randomized biopsies were performed, with additional targeted samples in each suspicious area identified on MRI. Detected cancers and their histological characteristics were compared between those two biopsy protocols. A micro focal cancer (MFC) was defined by the presence of less than 4mm of Gleason score 3+3 cancer on a single core.

RESULTS

Seventy-one consecutive patients were included. The overall detection rate was of 53% (38/71). It was of 70% (26/37) in the presence of suspicious area on MRI versus 35% (12/34) in the absence of any suspicious area (P=0.004). MRI-targeted biopsies alone detected three cancers, none of which was a MFC. 12-core biopsies alone detected 14 cancers, including ten MFC (71%). In 21 patients, prostate cancer was detected by both the MRI-targeted and 12-core biopsies. The Gleason score in the MRI-targeted area was the highest Gleason score in 90% of the cases. It was high (>6) in 76% (16/21) of the patients.

CONCLUSIONS

MRI-targeted biopsies detected less micro focal cancers than randomized 12-core biopsies. They did not seem however to decrease the detection of clinically significant cancers.