Elastography for the diagnosis of prostate cancer
This special form of transrectal ultrasound to improve the appearance of tumors and thus their detection. New things to learn was also in the German Association of Urology congress in 2008.
When a suspicious finding on palpation of the prostate (digital rectal examination, DRE ) or an elevated PSA value usually a transrectal ultrasound (initially TRUS ) performed. However, so many are not tumors from surrounding healthy tissue demarcated, and often no tumor behind an eye-catching range (see also transrectal ultrasound ). Therefore, TRUS is now used mainly to control the systematic multiple biopsy, the standard procedure for the diagnosis of prostate cancer (see also prostate biopsy ).
To improve the appearance of tumors and thus the accuracy of the biopsy, various new techniques in testing, including elastography. It is based on that tumors from healthy tissue in its elasticity may differ (hardness) (Hole 2006). The implementation is similar to the TRUS. In addition, it can be controlled by pressure on the prostate, the elasticity distribution map within the institution in real time, so to speak, producing a very detailed Tastbild.
After initial studies in patients location and extent of prostate cancer with elastography can be more accurately than with the TRUS alone (Sommerfeld 2003). According to later studies should be 80-100%, the sensitivity of the method, which means that 80-100% of the existing tumors were detected (Salomon 2008/1). This coincides with the publication, according to which, although the sensitivity was 98%, specificity but only 64% (Zey 2007). In about a third of the healthy, the finding was still so striking. Nevertheless, the authors considered the elastography for an additional method in the early detection, especially with an unremarkable DRE and TRUS and a not clearly elevated PSA level.
For a completely different result was a new study (Eggert, 2008): In elastography, the sensitivity was only 45% (at TRUS 39%), but the specificity 89% (when TRUS 78%). She was the TRUS so do not think and do not allow it to reduce the number of tissue samples or even to forego a biopsy, according to the authors. As limiting factors, they claim that the results of elastography are highly dependent on the experience of the examiner, tumors sometimes differ in their elasticity only slightly from normal tissues and there are also benign lumps (eg calcification, inflammation, scar). However, the devices are technically much improved now.
To determine the value of elastography for tumor detection, men were in another study with a secure means of biopsy prostate cancer before radical prostatectomy examined (Salomon 2008/1 +2). The authors compared the findings of elastography with those of the removed tissue, resulting in a sensitivity of 75% and a specificity of 77% resulted. They see it confirmed other studies and improve the appearance of suspicious areas compared with the previous ultrasound. But they also admit that the previously fixed diagnosis is a critical point and elastography is controversial. Further studies are needed, and a sole elastography-guided biopsy can not be recommended at present. In combination with a systematic biopsy whose application is very justified if no tumor was detected in a first biopsy.
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