MRI Sharpens Prostate Cancer Risk Stratification
Prostate cancer surgeons routinely use MRI to guide surgical planning, yet imaging findings are not used for risk stratification in standard prognostic models. A new meta-analysis suggests they should be.
The analysis, of 40 studies involving nearly 25,000 men undergoing radical prostatectomy, found that preoperative MRI findings offered independent prognostic value for biochemical recurrence, metastasis, and prostate cancer-specific death.
Specifically, extraprostatic extension, seminal vesicle invasion, and certain MRI quantitative metrics (such as high Prostate Imaging Reporting and Data System [PI-RADS] scores) were strongly associated with outcomes. That was after adjustment for established factors used in current prediction models from the National Comprehensive Cancer Network and other groups — including prostate-specific antigen level, digital rectal exam results, and biopsy Gleason grade.
“MRI appears to be a complementary prognostic layer,” researchers led by Georgios Agrotis, MD, PhD, of the Netherlands Cancer Institute, reported in JAMA Oncology.Article Key Points
The findings bolster the current use of MRI in surgical planning and support its formal incorporation into preoperative risk models to improve subsequent risk-based treatment decisions.
“This is the main message of our study,” Agrotis told Medscape Medical News. “The potential value is not only better prediction but also better personalization of care.”
Patients who appear similar based on traditional clinicopathological factors may in fact have different levels of risk that can be discerned by MRI, he said.
Adding MRI to widely used prognostic models could also standardize its use across centers, paving the way for multicenter studies to zero in on best practices, Agrotis noted.
Urologic oncologist Nicholas Pickersgill, MD, of the Memorial Sloan Kettering Cancer Center, New York City, also sees the potential.
In an accompanying editorial, he noted that while MRI is already used for nerve-sparing, lymph node dissection, radiation, and other decisions, “oncologists set aside the MRI results when predicting what the cancer will do.”
This meta-analysis, he added, “strengthens the case for reconsidering this omission,” though prospective studies are needed to confirm clinical benefit.
In the meantime, Pickersgill told Medscape Medical News that many centers, including his own, are developing in-house prognostic nomograms that include MRI findings to predict posttreatment recurrence and progression.
“The future of prostate cancer risk stratification almost certainly lies in models that integrate refined pathology, imaging, and molecular features alongside clinical variables to advance individualized treatment planning,” Pickersgill said.
One of the challenges, he added, will be determining exactly how to integrate prognostic information from MRI.
“Guideline committees should now define the evidentiary threshold required,” Pickersgill said.
In the meta-analysis, MRI-detected extraprostatic extension was associated with increased risks of all three outcomes the researchers considered: a twofold higher risk for biochemical recurrence (pooled hazard ratio [HR], 2.16), a threefold higher risk for metastatic failure (HR, 3.18), and a nearly 11-fold increase in the risk for prostate cancer-specific mortality (HR, 10.93).
Seminal vesicle invasion, meanwhile, almost tripled the risk for biochemical recurrence (HR, 2.74) and increased the risk for metastatic failure nearly sixfold (HR, 5.58).
Several quantitative MRI parameters were also prognostic for biochemical recurrence. The risk was roughly doubled when men had PI-RADS scores of 4 or 5 (HR, 2.15), tumor diameter of 20 mm or more (HR, 2.35), or low apparent diffusion coefficient values (HR, 2.39).
Overall, the analysis found, MRI-based T staging was a substantially stronger predictor of biochemical recurrence than clinical T staging based on digital rectal exam.
Agrotis and his colleagues acknowledged some limitations of their analysis. For one, MRI use might have been influenced by institutional practices or clinical indication, creating selection bias toward higher-risk disease. In addition, most studies had a primary endpoint of biochemical recurrence, while relatively few assessed metastatic failure or mortality — which, the researchers wrote, “limits inference regarding long-term outcomes.”
There was no external funding for the work. Agrotis and Pickersgill had no disclosures.
M. Alexander Otto is a physician assistant with a master’s degree in medical science and a journalism degree from Newhouse. He is an award-winning medical journalist who worked for several major news outlets before joining Medscape. Alex is also an MIT Knight Science Journalism fellow. Email:aotto@medscape.net.









