# Comparing Multigene Molecular Testing Results of MRI-Target Versus Systematic Prostate Needle Biopsies of Candidates for and Under Active Surveillance

## TL;DR

This study compares genetic test results from targeted MRI-guided and standard prostate biopsies to assess cancer risk in patients under active surveillance.

## Contribution

The study evaluates the utility of multigene testing for MRI-targeted versus systematic prostate biopsies during active surveillance.

## Key findings

- MRI-target cancers had similar risk scores to systematic cancers overall.
- Systematic GG2 cancers showed higher predicted mortality and metastasis risks compared to GG1 target cancers.
- ProlarisTM results were consistent across different time points of active surveillance.

## Abstract

Introduction: The multigene molecular testing of prostate cancer tissue after biopsy provides individualized information to guide further management. The utility of selective genetic testing for MRI-visible target versus systematic cancer in patients as well as during different time points of active surveillance (AS) is unknown. The objective of this study was to compare ProlarisTM results of MRI-target cancers versus systematic cancers on prostate needle biopsy as well as both during consideration for initial AS candidacy and candidacy for remaining on AS. Methods: Our prospectively maintained institutional multiparametric (mp) MRI prostate cancer active surveillance database (2013–2024) was queried for patients that underwent ProlarisTM genetic testing of positive biopsy cores. Baseline information for PSA, PSA density, and ProlarisTM calculated data were collected. Information on the timing of the Prolaris testing, defined as during the initial cancer diagnostic biopsy or on a subsequent confirmatory biopsy was collected. SPSS v29.0 was used to compare the selective ProlarisTM results of MRI-target cancers versus systematic cancers during different points of AS. Results: 264 patients with a ProlarisTM test were identified, 86 with MRI-target and 178 on systematic cancers. 182 ProlarisTM tests were sent on a diagnostic biopsy and 81 on a subsequent biopsy. Overall, MRI-target cancers had similar risk scores (3.23 vs. 3.14, p = 0.18). ProlarisTM scores were higher for GG2 systematic than GG1 target cancers (3.40 vs. 3.18, p = 0.023). The GG2 systematic lesion cohort also had higher predicted the 10-year disease-specific mortality (DSM) (3.40% vs. 2.30%, p < 0.01) and 10-year metastasis risk (1.90% vs. 1.20%, p = 0.013), and more aggressive recommended treatment. Analyses of the ProlarisTM results sent during a diagnostic biopsy yielded similar results. Finally, on an analysis of the ProlarisTM results sent during subsequent biopsy, a systematic GG2 biopsy was noted to have a higher 10-year DSM and metastasis rate, but similar risk scores and treatment recommendations. Conclusions: ProlarisTM tests can be sent at multiple time points of AS, and selectively for MRI-visible versus higher grade cancers. There is no consistent association between MRI-visible cancer and Prolaris risk profile. When utilizing multigene molecular testing in prostate cancer, each individual patient must be evaluated to decide the appropriate level of care.