Other diagnostic after negative prostate biopsy
If at a sampling no malignant tissue is found, the suspicion of prostate cancer (prostate cancer) but persists, the diagnosis must be continued. The possibilities for this have been identified on the German Association of Urology congress in 2006.
Important criteria for the decision to prostate biopsy are the result of digital rectal examination (see DRU ), the level of total PSA (t-PSA) and the proportion of free PSA (% f-PSA, PSA to seePSA determination ). Alone from these values, the risk for a positive biopsy estimate (detection of malignant tissue). This is done with nomograms (special tables) that have an accuracy up to 77%, even if the planned number of tissue samples (punching) is included.
The standard today are 8 stamping, with a prostate volume greater than 30ml 10-12 punching.For the extraction, integration and processing of the tissue samples are specific recommendations, but still no standardized procedure.
First, repeat biopsy
With a negative biopsy (no detection of malignant tissue) is not safe excluded prostate cancer.For it may be that an existing cancer stove was not hit. This raises the fundamental question for the further procedure. While there is still no uniform pattern for this, but recent studies have provided numerous clues.
After a Rebiopsie (repeat biopsy) should be performed when still a tumor is suspected. This is the case with detection of suspicious tissue (eg ASAP , HG-PIN ) with abnormal findings in the DRE or ultrasound (see TRUS ) and a persistently high or rising PSA level.
The Rebiopsie should include more punches than the initial biopsy (to about 20) and the transition zone of the prostate include (transitional zone, TZ, see emergence and forms of prostate cancer ). The rate of positive biopsies increases with the time interval after the initial biopsy. The ideal distance is, however, not yet clear. Recommended 3-6 months in the detection of ASAP and 1 year at evidence of HG-PIN.
Regarding the PSA is considered a Rebiopsie as more urgent, the higher are the values and the steeper they rise. The increase can be judged best with multiple measurements within two years and characterized with various methods of calculation:; (. Of engl velocity = speed) The PSA slope (engl. = slope) shows him most closely with the PSA-V are 0 , 75ng/ml/Jahr in the PSA-DT (of English. doubling time = doubling time) three years as a limit. This means that the PSA level may increase arithmetically per year to 0.75 ng / ml or more than double in three years, with higher values are suggestive of a carcinoma.
Falls and the second biopsy (the first Rebiopsie) is negative, then a so-called follow Saturationsbiopsie (saturation biopsy) that includes at least 20 cutting. There is a lack of accurate studies and at appropriate sampling schemes. Because it has been calculated that each milliliter of prostate a punch should be taken to detect an existing tumor with only 52% certainty, while for detection with 96% or 100% certainty even two or three punches per milliliter necessary would.
More possibilities in the diagnosis
In order to improve the detection of a possible presence of prostate cancer by negative biopsies, have been numerous and imaging and other procedures are investigated.Unfortunately, so far replace a new Gewebswebsentnahme (biopsy), but only contribute to more accurate detection, none of the methods described, partly experimental.
So showed Rebiopsien with special ultrasonic technology (Doppler technique with contrast medium) despite fewer punches (max. 5) a higher tumor detection rate as a standardized 10-punching biopsy, at least at low PSA level (2-4ng/ml) and small prostate volume (up to 40ml).
In the MRI (magnetic resonance imaging) Various modifications have been tested to increase their diagnostic value, or to implement them instead of ultrasound to assist Rebiopsie. It was found, for example, that the dynamic contrast-enhanced MRI is suitable for tumor detection, in contrast to conventional MRI and 3D MR spectroscopy it is rather a useful supplement, but not a replacement of the biopsies. Also provided an MRI with enhanced induction results similar to a conventional MRI with endorectal coil, which is therefore unnecessary.
The 11C-Cholin-PET/CT is a simultaneous examination using CT (computed tomography) and PET (positron emission tomography), in which the distribution of radiolabeled choline is determined in the body. She showed in a study of good detection rates of prostate cancer and lymph node metastases.
Another study found that by TURP (transurethral resection of the prostate) are locate central prostate cancers that are beyond a normal biopsy. Thus, the TUR-P is considered as a diagnostic possibility after repeated negative biopsies, when both urinary obstruction made by an enlarged prostate gland, in which this operation is standard anyway (benign prostatic syndrome, see BPS ).
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