Preoperative MRI assists decision-making during robotic prostatectomy
MedWire News: Preoperative prostate magnetic resonance imaging (MRI) helps surgeons evaluate the decision to use a nerve-sparing technique during robotic-assisted laparoscopic prostatectomy (RALP), suggest study findings.
RALP is a novel treatment that uses smaller incisions than those of open radical prostatectomy, but surgeons performing RALP lack tactile feedback, which could compromise their ability to evaluate neurovascular bundles.
"I think preoperative MRI will be useful for surgeons who are uncertain whether to spare or resect the nerves," said lead study author Daniel Margolis (University of California Los Angeles, USA) in an associated press release.
"Our surgeons feel that, compared with clinical information alone, MRI is worthwhile for all patients, because it identifies important information leading to a change in the surgical plan in almost a third of patients," he added.
In total, 104 men with biopsy-confirmed prostate cancer who underwent preoperative endorectal coil MRI of the prostate and subsequent RALP in 2004-2008 were included in the study.
MRI included T2-weighted imaging, diffusion-weighted imaging, dynamic contrast-enhanced imaging, and MR spectroscopy. Differences in surgical plans before and immediately following review of the MRI report were compared with actual surgical and pathologic results.
Following review of MRI results, the initial surgical plan was changed in 28 (27%) patients. A nerve-sparing technique was employed in 17 (61%) of these patients, while a non-nerve-sparing technique was used in 11 (39%) patients.
Overall, 6.7% of the patients had positive surgical margins. Patients who had their surgical plan changed to a nerve-sparing technique showed no positive margins on the side of the prostate. Positive margins coincided with pathologic stage T3 disease bilaterally in the case of bilateral positive margins and ipsilaterally in one case of left-sided positive margins. All other cases of positive margins occurred in stage T2 disease. Indeed, the specificity of prostate MRI in the differentiation of T2 from T3 disease was 97.5%.
"MRI can help localize the side of stage T3 disease so that only an ipsilateral neurovascular bundle may be resected; the contralateral side may safely undergo nerve-sparing resection to minimize postoperative incontinence or impotency," write Margolis and team in Radiology.
Margolis noted that for the approach to become commonplace, it will be necessary to find a better way to stratify which patients could benefit from preoperative MRI, and identify a more standardized way of acquiring and interpreting prostate MRI results.
"The former is something we are investigating now," said Margolis, adding: "The latter is something that a number of leading experts in prostate MRI are working toward. However, most centers already have this technology, so this may become widespread relatively soon."
By Ingrid Grasmo