MRI Cuts Risk of Nerve Damage in Prostate Surgeries

Preoperative MRI helps surgeons make better decisions about nerve-sparing procedures in men with prostate cancer, according to a study published online January 24 in the journal Radiology.

Radiologist Timothy McClure, MD, of the David Geffen School of Medicine at the University of California Los Angeles, and colleagues investigated endorectal coil MR imaging as a way to improve preoperative assessment of prostate cancer and the involvement of the neurovascular bundles.

They prospectively evaluated 104 prostate cancer patients who underwent preoperative endorectal coil MRI of the prostate and subsequent robotic-assisted laparoscopic prostatectomy, or RALP. Surgeons performing RALP lack tactile feedback, which may compromise their ability to evaluate neurovascular bundles – the collections of blood vessels and nerves that course alongside prostate. An aggressive surgical approach could unnecessarily damage the bundles and leave patients with loss of function, while an approach that is not aggressive enough may leave some cancer behind.

The researchers determined the differences in the surgical plan before and after review of the MRI report and compared them with the actual surgical and pathologic results.

Preoperative prostate MRI data changed the decision to use a nerve-sparing technique during RALP in 28 (27 percent) of the 104 patients. The surgical plan was changed to the nerve-sparing technique in 17 (61 percent) of the 28 patients and to a non-nerve-sparing technique in 11 patients (39 percent). The decision to opt for nerve-sparing surgery did not compromise oncologic outcome.

“I think preoperative MRI will be useful for surgeons who are uncertain whether to spare or resect the nerves,” said Daniel Margolis, MD, a UCLA radiologist and study co-author. “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.”

For the approach to become more commonplace, Margolis said that two things were needed: a better way to stratify which patients would benefit from preoperative MRI, and a more standardized means of acquiring and interpreting prostate MRI results.

Example of surgical plan changed to non–nerve-sparing technique. Images in 53-year-old man with PSA level of 14 ng/dL and biopsy Gleason score of 3 + 3 = 6 in two of six core specimens on the right. On the basis of these findings, bilateral nerve-sparing surgery was initially planned. After MR imaging, however, surgical plan was changed to a non–nerve-sparing technique on the right. (a) Coronal and (b) axial T2-weighted images show a low-signal-intensity mass (arrow) extending into the right seminal vesicle. (c) Apparent diffusion coefficient map shows restricted diffusion (arrow), corresponding to the low-signal-intensity focus on T2-weighted images. (d) Contrast-enhanced fat-saturated T1-weighted gradient-echo image shows enhancing nodule (arrow), corresponding to the area of low signal intensity on T2-weighted images. Final pathologic analysis demonstrated Gleason score of 4 + 3 = 7 and confirmed imaging findings of right
seminal vesicle invasion.
Images courtesy of Radiology