MRI-Assisted Guidance for Non-Essential Tissue Sampling (MAGNET): an Investigator-initiated, International, Multicentre, Prospective, Pairedcohort, Diagnostic Utility Study

The study aims to determine if a less painful and less invasive prostate biopsy approach is safe for certain men with a high risk of prostate cancer.

Currently, when a man has a suspicious MRI scan, standard medical guidelines recommend a "combined biopsy." This means the urologist performs a Targeted Biopsy (taking 3-5 tissue samples directly from the suspicious area seen on the MRI) followed immediately by a Systematic Biopsy (taking 12 additional samples blindly from the rest of the prostate). While this combined approach maximizes cancer detection, the 12 extra needles from the systematic biopsy increase the risk of bleeding, pain, and urinary infection.

Researchers believe that for men who already have a very high prostate-specific antigen (PSA) level and a highly suspicious MRI, the targeted biopsy alone might be enough to detect any dangerous cancer. In these high-risk men, the extra 12 systematic needles might offer little to no additional benefit ("diminishing returns").

In this study, 850 men will undergo the standard combined biopsy procedure. However, to test the researchers' theory with extreme precision, the tissue samples from the Targeted Biopsy and the Systematic Biopsy will be placed into completely separate, uniquely barcoded jars (the "One Core, One Jar" spatial mapping protocol). The pathologist will examine each tissue sample independently, without knowing which method was used to collect it.

By comparing the results within each patient, the study will determine exactly how many dangerous cancers were found exclusively by the systematic biopsy. If this number is clinically negligible (less than 5%) in men with high PSA levels, it will prove that the 12 extra needles are unnecessary for this specific group.

The ultimate goal of the trial is to safely "de-escalate" prostate cancer diagnostics-sparing high-risk men from the physical trauma, complications, and costs of unnecessary systematic sampling, while ensuring no dangerous cancers are missed.