Preoperative MR improves robot-assisted prostatectomy outcomes

Using preoperative MRI to direct intraoperative frozen-section (IFS) analysis during robot-assisted radical prostatectomy significantly reduced the rate of surgical margins that were positive for cancer, according to a study published online ahead of print in Radiology.

“The significantly lower rate of positive surgical margins compared with that in control patients provides preliminary evidence of the positive clinical effect of multiparametric MR imaging–directed IFS analysis for patients who undergo prostatectomy,” wrote Giuseppe Petralia, MD, of the division of radiology at the European Institute of Oncology in Milan, and colleagues.

Robot-assisted radical prostatectomy has become the dominant surgical approach for treating prostate cancer, accounting for four out of five radical prostatectomies performed in the U.S. in 2013, explained the authors. While this procedure can spare nerves and prevent damage to sexual function, by sparing neurovascular bundles the safety distance between cancerous tissue and surgical margins is reduced. “Therefore, the surgeon must balance the desire to minimize postoperative morbidity afforded by a nerve-sparing approach with the need to gain tumor control by avoiding positive surgical margins,” wrote Petralia and colleagues.

IFS analysis cuts sections from removed prostate that are frozen, stained and examined under a microscope to provide real-time histologic assessment of surgical margins. The authors sought to evaluate the use of multiparametric MRI to direct IFS analysis to sites that are highly suspicious for tumor contact with the prostatic capsule.

They conducted a retrospective analysis featuring 134 patients who underwent preoperative multiparametric MRI and nerve-sparing robot-assisted radical prostatectomy with IFS analysis and compared outcomes with a control group of 134 matched patients who underwent prostatectomy without MRI or IFS analysis.

Results showed that positive surgical margins were found in 7.5 percent of the MR/IFS analysis group compared to 18.7 percent of the control group. After factoring in differences in risk factors, patients who underwent MRI and IFS had one-seventh the risk of having positive surgical margins, according to the authors.

Petralia and colleagues pointed out that MRI directed the IFS analysis to the anterior or anterolateral aspects of the gland, areas that were unlikely to have been analyzed without preoperative MRI. “Moreover, the ability of multiparametric MR imaging–directed IFS analysis to provide timely, intraoperative confirmation of surgical margin status for anterior tumors may have application to newer surgical techniques such as complete anterior preservation.”