Diagnostic accuracy of transrectal elastosonography (TRES) imaging for the diagnosis of prostate cancer: a systematic review and meta-analysis

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Aboumarzouk et al. provide a comprehensive overview of transrectal elastosonography (TRES), sometimes simply referred to as elastography, in the diagnosis of prostate cancer. This represents a relatively new method in the detection of prostate cancer with the potential for further development. The current ‘gold standard’ prostate biopsy based upon standard grey-scale TRUS imaging is limited due to the highly variable appearance of prostate cancer, and the challenges of distinguishing benign from malignant tissue with grey-scale or colour Doppler [1]. There is a notable improvement in the Doppler detection of prostate cancer with microbubble contrast agents. Hypervascular prostate cancers are detected with fewer biopsy cores by using microbubble contrast-enhanced US (CEUS) with higher grade cancers more likely to be detected with the CEUS than with other TRUS methods [1,2].

Perhaps more important than the detection of all sites of prostate cancer is the preferential detection of clinically aggressive disease. Ideally, any imaging method that directs a prostate biopsy must improve on our ability to discriminate higher grade cancers from lower grade ones based on the Gleason score. A current major controversy is that PSA screening results in the detection of many clinically insignificant cancers, such that the risk of being diagnosed with prostate cancer is far greater than the risk of dying from the disease [3]. The prostate cancer controversy concerning screening and detection focuses on the over-diagnosis and over-treatment as significant adverse effects of PSA-based prostate cancer screening [4].

Our previous elastography work showed that areas of abnormal elasticity were more than twice as likely to be prostate cancer as areas with normal elasticity [5]. To our knowledge, our study was the first to directly compare elastography to other TRUS methods including colour Doppler. A positive colour Doppler was more strongly associated with high-grade cancer, whereas positive elastography was associated with both moderate- and high-grade cancer.

This comprehensive state of the art review of TRES notes 10 studies reporting higher detection rates for prostate cancer with a higher Gleason score. Further confirmatory work in this area, including direct comparison with other US methods and developing MRI technologies, is essential if these elastography based biopsy methods are ultimately to be incorporated into future prostate cancer care.

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