Over the past decade, it has become common practice to perform MRI prior to prostate biopsy. One of the aims of pre-biopsy MRI is to reduce unnecessary prostate biopsies by focusing on only clinically significant cancers (CSCa). Although there have been many reports on the usefulness of MRI for detecting CSCa, it has not been verified whether the "widespread use of pre-biopsy MRI" contributes to the "improvement in the detection rate of CSCa. In this study, we examined pre-biopsy MRI rates and cancer detection rates per year over the past 10 years.

We retrospectively examined the data of patients who underwent prostate biopsy from 2013 to 2022 at our institution (2086 cases). We determined “pre-biopsy MRI rate (pre-MRI rate)” as “percentage of cases with MRI prior to biopsy per total number of prostate biopsies per year”. CSCa was defined from the pathology result as previously reported. Cases diagnosed with cancer and treated immediately were defined as “active treatment cancer (ATCa)”. The relationships between pre-MRI rate and three patterns (total cancer, CSCa, ATCa) detection rates per year were analyzed by correlation coefficient and regression analysis.

Around 2013, pre-MRI rate was only about 20%, but in the last five years it has been almost 90% or more. Coefficient of determinations and regression analyses were r2=0.82; y=0.28x+46.87 (p<0.001), r2=0.61; y=0.33x+36.77 (p=0.007), and r2=0.81; y=0.24x+44.03 (p<0.001) for total cancer, CSCa, and ATCa detection rates, respectively.

This is the first study showing that widespread use of pre-biopsy MRI interpreted by annual pre-MRI rates contributes to the improvement in the detection rates of CSCa and ATCa. Changes over the past decade would be beneficial to patients because unnecessary biopsies can be avoided.