The value of MRI prior to surgery as a treatment for localized prostate cancer

A recent media release from the Radiological Society of North America (RSNA) is headed, “Preoperative MRU may reduce risk of nerve damage in prostate cancer surgeries” … and this is absolutely true. The problem, however, is that it is only appears to be true for about a quarter of all the men undergoing surgery, so there is an unanswered question at this time about who really needs to have an endorectal coil MRI prior to surgery and who is going to get absolutely no benefit from such a test.

McClure et al. have reported data from a prospective study designed to investigate whether data from preoperative endorectal coil magnetic resonance imaging had any effect on surgeons’ decisions to try and preserve neurovascular bundles and the precision of surgical margins in men scheduled to be treated with robotic-assisted laparoscopic prostatectomy (RALP). The stidy was carried out between April 2004 and January 2008.

Here are the key data regarding the way this study was conducted:

  • The study included 104 consecutive patents with biopsy-proved prostate cancer who were scheduled for RALP.
  • All patients were given a preoperative, endorectal coil MRI of the prostate and a subsequent RALP.
  • MRI imaging was performed at 1.5 T and included T2-weighted imaging (n = 104), diffusion-weighted imaging (n = 88), dynamic contrast-enhanced imaging (n = 51), and MR spectroscopy (n = 91).
  • A single surgeon planned the surgery first on the basis of clinical information only and then again after being able to see the final MRI report.
  • Differences in the surgical plan before and after review of the MR imaging report were compared with the actual surgical and pathologic results..

And now here is what the authors found:

  • After seeing the MRI report, the surgeon changed his initial surgical plan for 28/104 patients (27 percent).
    • For 17/28 patients (61 percent), the plan was changed from non-nerve-sparing to a nerve-sparing technique.
    • For 11/28 patients (39 percent), the plan was changed from a nerve-sparing to a non–nerve-sparing technique.
  • 7/104 patients (6.7 percent) had positive surgical margins.
  • In men whose  plan was changed from non-nerve-sparing to a nerve-sparing technique, there were no positive margins on the side of the prostate with a change in treatment plan.

Quoted in the RSNA media release, one of the co-authors of this paper, Dr. Daniel Margolis, points out the following:

There is a learning curve for prostate MRI.  What we and others have found is that one has to select patients where there is likely to be a benefit from the imaging.

He goes on to point out that we need a better way to stratify which patients would benefit from preoperative MRI, and a more standardized means of acquiring and interpreting prostate MRI results, and states that:

The former is something we are investigating now. The latter is something that a number of leading experts in prostate MRI are working toward.

We do seem to have a way to go yet before we know best how to apply what type of MRI in the presurgical management of men with localized prostate cancer.

One Response

  1. in this case, AMEN to your last sentence.

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