Diagnosis of bladder tumours
Every case of suspected bladder tumour must be clarified by means of cystoscopy. Furthermore, every clarification of a suspected bladder tumour includes urine analysis, sonography of the kidneys and the bladder and, if necessary, x-ray imaging of the kidneys using contrast medium.
Cystoscopy / Photodynamic diagnosis (PDD)
Cystoscopy is usually performed under local anaesthesia and serves to detect changes in the urethra, the urinary bladder and the ureteral orifices to the urinary bladder. Tumours of the urinary bladder usually appear as cauliflower-shaped growths emerging from the bladder wall.
Under certain circumstances, it may be difficult to detect a bladder tumour that is flat instead of growing into the bladder. To better visualise these tumours, what is referred to as photodynamic diagnosis can be used. Our department was one of the first to use this technique in Germany.
This technique uses a special fluorescent agent (Hexvix®, GE Healthcare) that accumulates in the tumour tissue after coming into contact with the bladder. The medical solution is introduced via a thin bladder catheter and is safe for the patient. The active substance is absorbed by tumour cells to a greater extent, causing them to emit red light under blue-light illumination. As a result, tumours can be better recognised and completely removed.
The image on the left shows the bladder tumour under conventional light
The image on the rights shows the bladder tumour under fluorescent light (glowing in red)
Various urine-based markers are available for the urine-based detection of bladder cancer. These are based firstly on changes in the cells contained in the urine and secondly on the measurement of proteins contained in the urine. Since the various tests are based on different methods, the accuracy of detecting bladder cancer can be improved significantly by combining these tests (Todenhöfer et al., Cancer Cytopathology 2013). The Department of Urology Tübingen is counted among the global leading centres for the urine-based diagnosis of bladder cancer.
Urine cytology test
The longest- and best-established marker is the conventional urine cytology test, which involves special staining of centrifuged urine and microscopic examination of the cells contained in the urine. Poorly differentiated tumours and what are referred to as carcinomas in situ can be detected relatively reliably by means of the urine cytology test. By contrast, the sensitivity for highly differentiated papillary tumours (pTaG1) is limited and the test can produce negative results although a tumour is present.
The image shows a urine cytology test; the cells of the urinary sediment are stained with Papanicolaou stain and examined for typical changes of malignant cells