If you’re a real estate developer planning to build a new house, you start with the groundwork—literally. Before you start excavating, you have analysts determine the basics: the type of soil, the water table, and any flood risk. You want to know the important foundation factors that help predict the future stability of the construction. Then you and your architect can plan the size and shape that will best fit the construction site.

This is similar to the process that goes into planning a treatment strategy for prostate cancer (PCa). It’s essential to know such basics as patient age, PSA, Gleason grade, tumor stage, etc. This provides predictive information for planning a strategy that best fits an individual’s PCa. It may include a menu of choices that range from nonaggressive to aggressive: active surveillance, focal ablation, partial gland ablation, total gland ablation, radiation, radical prostatectomy.

MRI: noninvasive risk stratification

Gathering patient information enables risk stratification, meaning assigning a risk level. As a general rule of them, the lower the risk, the less aggressive the treatment menu. There are three main risk categories: low, intermediate, and high risk. Until multiparametric MRI (mpMRI) came into wide use, risk stratification depended on a definitive diagnosis obtained by a needle biopsy. However, mistakes were not uncommon. A conventional 12+ core biopsy guided by transrectal ultrasound (TRUS) is essentially random, unable to visually identify and target the tumor. As such, areas of intermediate-to-high risk PCa were missed, leading to under-diagnosing the true nature of the tumor and possibly under-treating it.

Two new studies were published in the autumn of 2024, showing that mpMRI that can reveal aggression level before and even after a biopsy.

1. Risk classification for men on active surveillance (AS) – This study determined how a baseline MRI PI-RADS score could predict the chances of reclassifying AS patients to a higher risk level. The conclusion was based on data from nearly 1500 patients on AS for low to intermediate risk PCa. Patients were determined candidates for AS by their initial MRI (which gave the baseline PI RADS score) and their diagnostic biopsy (which gave their Gleason grade). At least 6 months after beginning on AS, patients had a follow-up biopsy. The Gleason grade from this biopsy was correlated with their baseline PI-RADS. The authors discovered that patients whose baseline PI RADS score equal to or greater than 4 were at increased risk of reclassification, the usual trigger to move from AS to active treatment because of increased tumor growth and/or aggression. They concluded that “…baseline MRI PI-RADS score was significantly associated with early biopsy reclassification in men undergoing AS. …Clinical implications include improved upfront AS risk stratification with MRI [emphasis ours], particularly important in the NCCN favorable intermediate-risk group, along with tailoring intensity of surveillance.”^[i]
2. MRI gives visual tumor characteristics that predict reclassification – This smaller study involved 156 patients whose biopsy results indicated grade group 1 PCa (very low risk) and whose PI RADS lesions were scored at 3 or greater. All patients were followed until either re-biopsy or radical prostatectomy (RP). Both re-biopsy and RP provided tissue samples again indicated their grade group. At follow-up, the research team compared the mpMRI characteristics between A) those who continue to be grade group 1 vs. B) those who were upgraded to grade group 2 or higher. They found that those in group B had the following characteristics: 1) greater contact length of the index lesion to the prostate capsule (edge), PI-RADS score 4 or 5, and greater restriction of water molecules in tumor. They concluded, “MRI reveals important information about PC aggressiveness and should be incorporated into clinical decision-making when ISUP-1- PC is diagnosed. In cases of specific MRI characteristics adverse to the histopathology, early re biopsy might be considered.”^[ii]

What all this boils down it this: MRI can identify and clarify the probability that what seems to be low risk cancer on biopsy may actually harbor characteristics indicating it poses a threat of rapid growth or progression. The value of integrating mpMRI into the detection and diagnostic pathway is its contribution to the future treatment success. If you think of a PCa treatment plan as similar to designing a blueprint for a durable, sturdy new home, you want to make sure it gets built on the right foundation. Let MRI be part of the groundwork that underlies the design. And remember: choose an experienced radiology team and a center equipped with a powerful 3T magnet, like the Sperling Prostate Center.

NOTE: This content is solely for purposes of information and does not substitute for diagnostic or medical advice. Talk to your doctor if you are experiencing pelvic pain, or have any other health concerns or questions of a personal medical nature.

References

[i] Nandalur KR, Shen C, Zhao L, Al-Katib S et al. Association of Baseline Magnetic Resonance Imaging Prostate Imaging Reporting and Data System Score With Prostate Cancer Active Surveillance Early Biopsy Reclassification: Data From the Michigan Urological Surgery Improvement Collaborative (MUSIC). J Urol. 2024 Oct;212(4):571-579.
[ii] Boschheidgen M, Schimmöller L, Radtke JP, Kastl R, Jannusch K, Lakes J, Drewes LR, Radke KL, Esposito I, Albers P, Antoch G, Ullrich T, Al-Monajjed R. MRI characteristics predict risk of pathological upgrade in patients with ISUP grade group 1 prostate cancer. Eur Radiol. 2024 Sep 13.