Pre-op mpMRI variables predict post-RARP recurrence

Bethesda, MD-Findings from preoperative multiparametric magnetic resonance imaging (mpMRI) may enhance risk stratification, surgical planning, and patient counseling for men with prostate cancer, according to researchers from the National Institutes of Health, Bethesda, MD. 

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In a study presented at the 2015 AUA annual meeting in New Orleans, the authors reported that three preoperative mpMRI variables-suspicion score, total prostate volume, and extracapsular extension (ECE)-independently predicted biochemical recurrence (BCR) after robot-assisted radical prostatectomy (RARP). In addition, a nomogram they developed that incorporated the three predictive mpMRI variables with preoperative PSA accurately predicted the risk of BCR (concordance index=0.79).

“Going forward, it will be important to validate our nomogram using data from other institutions and to compare its performance with existing instruments for predicting BCR,” said first author Richard Ho, who was an NIH National Cancer Institute medical research scholar at the time of the study.

“However, we believe our findings provide strong support for the idea that preoperative mpMRI can have a role for staging patients and supporting clinical decision-making,” added Ho, who worked on the study with Peter Pinto, MD, and colleagues.

He added that the information provided by the NIH mpMRI nomogram might also be useful for helping to set patient expectations prior to surgery.

“The decision on who should get adjuvant therapy is ultimately guided by findings at surgery. Use of this nomogram, however, may augment our ability to accurately counsel men preoperatively about their risk and minimize the chance that they will be surprised and disappointed if adjuvant therapy is recommended postoperatively,” said Ho, currently a medical student at Albert Einstein College of Medicine, New York.

The study assessing the utility of findings from preoperative mpMRI for predicting BCR after RARP included data from 370 men operated on at the NCI between May 2007 and January 2015. All of the men evaluated for the study had PSA follow-up, a good-quality mpMRI, and no history of receiving preoperative radiation or hormonal therapy or postoperative adjuvant therapy.

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During a median follow-up of 23.1 months, 39 men (10.5%) developed BCR, which was defined as a serum PSA ≥0.2 ng/mL with a subsequent confirmatory value.

Next: BCR, no BCR subgroups compared

BCR, no BCR subgroups compared

Univariate analyses showed statistically significant differences between the BCR and no BCR subgroups with respect to mean preoperative PSA, clinical stage distribution, MRI suspicion score, and presence of ECE on MRI. In addition, there was a trend for the BCR subgroup to have a significantly smaller total MRI prostate volume.

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The two subgroups were similar with respect to total MRI lesions and the finding of seminal vesicle invasion, which was present in only 5.1% of men who developed BCR and 2.7% of those in the no BCR subgroup.

Total prostate volume on mpMRI became a statistically significant predictor of BCR on multivariate analysis, and significant associations were maintained for preoperative PSA, MRI suspicion score, and ECE on mpMRI.

Next: Statistically significant associations between BCR-free survival probability with both mpMRI suspicion score and ECE on mpMRI

The authors also undertook Kaplan-Meier analyses that showed statistically significant associations between BCR-free survival probability with both mpMRI suspicion score and ECE on mpMRI. The estimated 5-year BCR-free survival probability was 100% for men with a low mpMRI suspicion score, 82% for men with a moderate mpMRI suspicion score, and 62% for those with a high mpMRI suspicion score.

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The 5-year BCR-free survival probability was 89% among men with no ECE on MRI, but fell below 60% by 5 years among men found to have ECE on mpMRI.

Biopsy Gleason score was not assessed as a possible predictor of BCR in the analyses presented; however, researchers were planning to investigate its incorporation in their model.

Ho also noted the major limitations of this nomogram for predicting BCR are the short-term follow-up and the fact that the in-house NIH MRI scoring system was used. PIRADS2 is now being used at the NIH for all prostate MRIs.

More on Prostate Cancer:

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Utility of PCa markers in African-Americans differs

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