Can a single, specialized MRI scan replace bone and CT scans for men with high-risk prostate cancer?


A recent paper by a team of Belgian researchers has suggested that diffusion-weighted. whole-body magnetic resonance imaging (DWWBMRI) may be able to replace historic forms of imaging — bone scans and contrast-enhanced CT scans and/or standard MRIs of the pelvis in the work-up of men at high risk for metastatic prostate cancer.

Quite apart from the potential simplicity of a single-scan, routine process for the detection of metastatic prostate cancer (as opposed to the use of two or three different scans), it is worth noting that the difficulties associated with the sourcing of radioactive technetium-99m (an essential element in the historic process for bone scans) has actually been a significant problem in recent years. If bone scans could be replaced, then there would be a significant decline in the need for technetium-99m.

The article by Lecouvet et al. describes the detailed evaluation of 100 consecutive patients believed to be at high risk for metastatic prostate cancer. Each patient was given three separate imaging tests: a DWWBMRI, a contrast-enhanced CT scan, and a bone scan that could be completed with targeted X-rays (BS/TRX) if the initial bone scan data were equivocal. Four independent reviewers evaluated all of the images.

Here is a summary of the key results of the study:

  • The sensitivity and specificity of the BS/TXR were 86 percent and 98 percent, respectively.
  • The sensitivity and specificity of the DWWBMRI were 98 percent and 98 to 100 percent, respectively.
  • The first and the second image readers identified bone metastases in 7 and 8 patients, respectively, among 55 men with negative BS/TXR results.
  • The sensitivity and specificity of  contrast enhanced CT scans for detecting enlarged lymph nodes were 77 to 82 percent and 95 to 96 percent, respectively.
  • The sensitivity and specificity of DWWBMRI for detecting enlarged lymph nodes were 77 to 82 percent and 96 to 98 percent, respectively.
  • The sensitivity and specificity of the combination of BS/TXR + CT for detecting bone metastases and/or enlarged lymph nodes were 84 percent and 94 to 97 percent, respectively.
  • The sensitivity and specificity of DWWBMRI for detecting bone metastases and/or enlarged lymph nodes were 91 to 94 percent and 91 to 96 percent, respectively.

The authors conclude that DWWBMRI “outperforms BS/TXR in detecting bone metastases and performs as well as CT for enlarged lymph node evaluation.” They go on to state their opinion that DWWBMRI could, in fact, replace the current multi-image work-up for the evaluation of bones and lymph nodes in men at high risk for metastatic prostate cancer.

Clearly, others will need to be able to shown that they can replicate theses data before there is any pressure to actually make such changes in the work-up of men with high-risk disease.

One Response

  1. Impressed with the consistent findings from four different readers. I wonder if that will be replicated.

    Does anyone have cost data for the comparison?

    Would the avoided cost of prostatectomies on metastatic cancer offset the added costs for a pelvic scan as opposed to whole body?

    I realize that a big assumption has to be made about how many unnecessary surgeries are performed. Perhaps the inverse, per scan how many surgeries?

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