MP53-15: MRI-directed biopsy for primary detection of prostate cancer: MRI In-Bore vs MRI-transrectal ultrasound fusion-targeted techniques

Francesco Del Giudice*, Maurizio Del Monte, Stefano Cipollari, Martina Pecoraro, Marco Bicchetti, Emanuele Messina, Ailin Dehghanpour, Alessandro Sciarra, Ettore De Berardinis, Rome, Italy, Benjamin I. Chung, Stanford, CA, Carlo Catalano, Valeria Panebianco, Rome, Italy

Introduction: We aimed to compare the detection rates of overall prostate cancer (PCa) and clinically significant PCa (csPCa) and the median percentage of cancer per biopsy core between MRI-guided In-bore and MRI-TRUS fusion-targeted biopsy (TBx).

Methods: In this retrospective study, 223 patients who underwent prostate multiparametric MRI (mpMRI) and subsequent MR-directed biopsy were included. A multivariable logistic regression model was developed to assess whether the biopsy technique (MRI-TRUS or MRI In-Bore) was an independent predictor for both the outcome of PCa and csPCa diagnosis. All the regression models were adjusted for age ( <70 vs. >/=70 years), PSA (ng/dl), PSA density ( <0.15 vs. >/=0.15), pre-Bx PI-RADS score (3 vs 4–5) as well as lesion volume (ml), location (transitional/anterior vs peripheral) and level (base, mid-gland, apex). According to the available literature and to the cohort quantitative descriptive distribution, after having assumed a relevant threshold of neoplastic median per-core percentage =50%, the same regression model was implemented to test the ability of one technique over the other to better characterize the overall sampled tumor tissue within the biopsy cores.

Results: Per-patient PCa and csPCa detection rates were 140/223 (62.8%) and 97/223 (43.5%), respectively. PCa-DR was 73/117 (62.4%) and 67/106 (63.2%) for MRI-TRUS and MRI In-Bore TBx (p = 0.9), while csPCa detection rate reached 50/117 (42.7%) and 47/106 (44.3%), respectively (p=0.81). The median per-patient percentage of malignant tissue within biopsy cores was 50% (IQR: 27–65%) for PCa and 60% (IQR: 35–68%) for csPCa, with a statistically significant difference between the techniques. At multivariable logistic regression analyzing only index lesions, the implementation of MRI-TRUS or In-Bore TBx was not independently associated with an increased ability of one technique over the other for both PCa and csPCa detection (ORPCa: 0.67, 95% CI: 0.43–1.51 and ORcsPCa: 0.72, 0.37–1.54). Differently, when analyzing the diagnostic outcome for the positive biopsy sampling threshold >50% within the overall biopsy core length, MRI In-Bore TBx was independently associated with more than threefold ability to reach the outcome in the case of PCa but not for csPCa (ORPCa: 3.26, 95% CI: 1.37–7.12, and ORcsPCa: 2.17, 95% CI: 0.82–5.34).

Conclusions: No statistically significant difference in the detection rate of MRI In-bore and MRI-TRUS fusion TBx was found. MRI In-bore TBx showed higher per-core percentage of malignant cells.

Source of Funding: None