Pre-RP MRI does not affect surgical outcomes

Boston-Results of a retrospective case-cohort study show no significant differences in surgical outcomes among men who did and did not have preoperative magnetic resonance imaging (MRI) of the prostate prior to radical prostatectomy for prostate cancer.

Commentary - Prostate MRI: Value in surgical planning?

The research, which was presented at the AUA annual meeting in Boston by urologists from Washington University School of Medicine, St. Louis, included 192 men who received prostate MRI within 6 months of prostatectomy. They were identified from 589 men who underwent prostatectomy for prostate cancer between January 2012 and June 2016 and then matched 1:1 using propensity scoring analysis based on age, Charlson Comorbidity Index, PSA, body mass index, and biopsy Gleason score with men operated on without preoperative prostate MRI.

Surgical outcomes analyzed were operative time, estimated blood loss, perioperative complications, lymph node yield, and positive surgical margin rate. There was a trend for a higher complication rate in patients who had preoperative MRI compared with those who did not (24.0% vs. 16.7%; p=.076), but none of the surgical outcomes were significantly different between groups. In regression analyses controlling for all measured variables, preoperative MRI was not predictive of any of the measured surgical outcomes.

Next: Findings do not support hypothesis

Findings do not support hypothesis

“Prostate MRI is increasingly being utilized in the diagnosis of prostate cancer. The findings of this study, however, did not support our hypothesis that it could help guide surgical planning and therefore have a positive effect on surgical outcomes,” said co-author Michael Glamore, MD, urology resident at Washington University.

“Therefore, we would not recommend the routine use of preoperative MRI for the purpose of surgical planning in patients already diagnosed with prostate cancer who have chosen to undergo prostatectomy,” added Dr. Glamore, who worked on the study with Gerald Andriole, MD, and colleagues.

Dr. Glamore noted that the study design did not include a sample size calculation and that it cannot be concluded definitively from the study that preoperative MRI does not affect the surgical outcomes that were analyzed.

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Nevertheless, comparisons of baseline characteristics of the two patient cohorts showed that the propensity score matching was successful. In addition, variables identified as independent predictors of surgical outcomes in the regression analyses were consistent with previously described prognostic factors. Specifically, increased Charlson Comorbidity Index was a predictor of perioperative complication risk, and associations were noted between higher biopsy Gleason scores and both lymph node yield and positive surgical margins.

“Failing to identify these established prognostic variables would cause us to question more if our findings on the impact of preoperative MRI were not real,” Dr. Glamore said.

Dr. Glamore also noted that the majority of men in the control group had undergone preoperative computed tomography of the abdomen and pelvis. However, he discounted the possibility that the CT imaging was a confounding factor considering that MRI provides better information on features that are relevant to preoperative planning; ie, extracapsular extension and seminal vesicle invasion.

Surgeons were not surveyed to determine whether the findings of MRI affected their approach. Data on sexual function and urinary incontinence are available, and the authors are planning an analysis to determine whether there is any difference in those patient-reported outcomes between men who do and do not have MRI prior to radical prostatectomy.

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