Predictors of prostate cancer detection in fusion biopsies
Introduction- Prostate MRI-US fusion biopsies are becoming a standard procedure to diagnose prostate cancer. Most series thus far focus on the use of a single fusion software. In addition, to the best of our knowledge no prior series compared between the accuracy of transrectal to the transperineal approach to fusion biopsies.
We aim to examine predictor of accuracy using different approaches and devices of MRI-US fusion biopsies.
Methods- We used our prospective MRI-US fusion database to collect data on all fusion biopsies performed at our institution between 04/2014-08/2017. We performed a multivariable logistic regression analysis to determine independent predictors of prostate cancer and clinically significant (GLS≥7) prostate cancer diagnosis. Predictors included in the analyses were: age, PSA level, family history, previous biopsies (yes, no), prostate size (volume on MRI), PIRADS rank, location of MRI lesion (anterior, TZ, PZ, apex, midgland, base), transrectal vs transperineal, fusion software (biojet DK Vs Navigo UcCare).
Results- We completed 779 fusion biopsies (523 transrectal and 256 transperineal). Patients median age was 64 (IQR 60-72) and median PSA 6.33 (IQR 3.67-10.05). Prostate cancer was diagnosed in 358 (46%), significant cancer (GLS≥7) was diagnosed in 239 (31%).
On multivariable analysis, independent predictors were: PIRADS (REF-PIRADS3, PIRADS4 OR 1.75 95%CI 1.55-1.9 ; PIRADS5 OR 2.4 95%CI 1.7-3.1 (p=0.001)), prostate size ((OR 0.9 95%CI 0.77-0.93), and transperineal biopsy (OR 1.15 95%CI 1.1-1.4). The same predictors remained significant for higher risk prostate cancer.
Conclusions- In this study we found three independent predictors of accuracy in a large series of fusion biopsies. Since size and PIRADS level are patient dependent predictors that cannot be altered. The only surgeon level predictor that is modifiable is the biopsy approach. Although transperineal biopsies require larger resources (OR time and equipment) it seems to increase detection rate. A randomized study is needed to confirm these results.