Additional value of magnetic resonance-targeted biopsies to standard transrectal ultrasound-guided biopsies for detection of clinically significant prostate cancer

Abstract

Objective: The aim of this study was to evaluate the additional value of magnetic resonance imaging-targeted biopsy (MRI-TB) to standard transrectal ultrasound-guided biopsy (SB) for detection of clinically significant prostate cancer (PCa). An additional aim was to compare the biopsy results to MRI evaluation using a Likert scale.

Materials and methods: Patients with newly diagnosed localized PCa (n = 53) by clinical routine SB were prospectively included. The majority of the patients were scheduled for curative therapy before enrollment. The patients underwent multiparametric MRI (mpMRI) at 3 T using an endorectal coil followed by two MRI-TBs, using ultrasound with cognitive fusion. All included patients underwent MRI-TB, even those who had low to very low suspicion of significant PCa on mpMRI. The detection rate of significant cancer on SB versus SB + MRI-TB was compared in the 53 included patients and with whole-mounted histopathology as reference in 34 cases. Comparison of the biopsy results to MRI evaluation and interreader agreement calculation of five-point Likert score evaluation were performed.

Results: In total, 32 significant (Gleason ≥7) PCa were detected by SB, while SB + MRI-TB detected an additional five significant PCa. MRI-TB alone detected 20 and missed 17 significant PCa. Ten of the significant PCa cases missed by MRI-TB had a Likert score of 3 or lower. Interreader agreement using the Likert scale was high, with a kappa value of 0.77 (95% confidence interval 0.63–0.92, p < 0.0001).

Conclusion: Detection of significant PCa increased by adding MRI-TB to SB. This may not be of enough clinical value to justify the use of targeted biopsies in this patient group.

Keywords:

• Magnetic resonance imaging
• prostatic neoplasm
• targeted biopsies
• transrectal ultrasound-guided biopsy

Acknowledgements

The authors thank their colleagues at the Urology Department, Uppsala University Hospital, for referring patients; and the 3 T MRI unit for carefully conducting the study.

Disclosure statement

The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.

Additional information

Funding

The Swedish Cancer Society funded the study.