Magnetic Resonance Imaging-guided In-bore and Magnetic Resonance Imaging-transrectal Ultrasound Fusion Targeted Prostate Biopsies: An Adjusted Comparison of Clinically Significant Prostate Cancer Detection Rate

Background: With the increasing adoption of targeted prostate biopsies, it becomes important to understand the strengths and shortcomings of the techniques available for targeting suspicious lesions.

Objective: To compare clinically significant prostate cancer (csPCa) detection rate with magnetic resonance imaging-transrectal ultrasound (MRI-TRUS) fusion versus in-bore biopsy in men with abnormal multiparametric MRI (mpMRI).

Design, setting, and participants: This single-center, retrospective analysis of prospectively generated data included all men with abnormal mpMRI and fusion or in-bore biopsy between May 2017 and April 2018. Grade group (GG) 2-5 cancers were considered csPCa.

Outcome measurements and statistical analysis: Detection of csPCa was adjusted according to patient- and lesion-related characteristics using propensity score weighting. Secondary endpoints included the detection of clinically insignificant tumors and the rate of GG upgrade from biopsy to prostatectomy specimen. Analyses were performed at patient and lesion levels.

Results and limitations: A total of 103 and 300 men were included in the in-bore and fusion cohorts, respectively. On a per-patient basis, in-bore biopsies detected a higher proportion of csPCa (61%, 63/103) than fusion plus systematic biopsies (47%, 141/300; adjusted odds ratio [OR]: 2.1, 95% confidence interval [CI]: 1.6-2.8, p<0.0001). In-bore biopsies also detected fewer (11%, 11/103) clinically insignificant cancers than fusion biopsies (18%, 53/300; OR: 0.5, 95% CI: 0.3-0.8, p=0.001). Of those who had radical prostatectomy, GG upgrade after surgery was seen in 17% (4/24) of the men in the in-bore cohort and in 27% (22/82) of the men in the fusion cohort (p=0.55).

Conclusions: MRI-guided in-bore biopsies detected more clinically significant and fewer insignificant prostate cancers than MRI-TRUS fusion targeted biopsies. Further cost-utility and patient outcome analyses are needed.

Patient summary: In-bore biopsies (where the patient is on the magnetic resonance imaging [MRI] scanner itself) detected more aggressive cancers and fewer indolent cancers than fusion (where software blends MRI and ultrasound images) biopsies. These findings may help patients and physicians choose the best biopsy approach.