Study shows newest version of PI-RADS improves cancer diagnosis

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 - prebiopsy MR prostate cancer
Prebiopsy MR image of prostate revealing 7-mm lesion.
Source: (Radiology 2013; 268:461-469)

The second version of the Prostate Imaging Reporting and Data System (PI-RADS) is effective at preoperatively predicting clinically significant prostate cancers, according to results of a Korean study published online in the journal  Radiology.

The reporting system, aimed at standardizing the interpretation and systematic reporting of prostate MRI, is similar to other cancer reporting systems like BI-RADS (breast imaging) and LI-RADS (liver imaging) that have seen widespread adoption due to their ability to quickly and accurately communicate a patient's cancer risk.

Recently released by the American College of Radiology, the second version of PI-RADS has a simplified scoring system that focuses on detecting significant prostate cancers, says lead author Sung Yoon Park, MD, PhD, and his colleagues from Yonsei University College of Medicine in Seoul.

“The overall five-point scale used in PI-RADS version 2 is not designed for every cancer but for clinically significant cancer that may require further work-up or target biopsy,” the authors wrote. “However, its clinical utility has not been fully validated.”

To test the new version of PI-RADS, Park and his team performed a retrospective study on 425 prostate cancer patients who had undergone MRI and radical prostatectomy, investigating preoperative parameters such as prostate-specific antigen, biopsy Gleason score, greatest percentage of the core, percentage of the positive core number, and PI-RADS version 2 scores with MRI, which were performed by two independent readers.

Their findings showed that all of the preoperative parameters were significant for clinically significant prostate cancer. However, PIRADS score was the only significant parameter for both readers, with excellent interreader agreement for PI-RADS scores of 4 or greater.

“The use of PI-RADS version 2 allowed for acceptable diagnostic performance in predicting clinically significant prostate cancer,” the researchers wrote. “Our results suggest that PI-RADS version 2, as a more user-friendly tool, allows for comparable or better reproducibility than with the previous version.”

While the findings are a promising step forward for PI-RADS and the preoperative prediction of prostate cancers, Park and his colleagues believe more studies are necessary to validate the reporting system and further improve cancer diagnosis.

“The assessment of the likelihood of clinically significant cancer using surgical cases alone may not represent actual probability of clinically significant cancer according to the PI-RADS score,” the authors concluded. “A prospective study including nonsurgical cases may be required to assess that.”