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Bladder cancer (BC) is among the most expensive oncological diseases. Any improvement in diagnosis or therapy
carries a high potential for reducing costs. Fluorescence cystoscopy relies on a selective formation of Protoporphyrin IX
(PpIX) or more general photoactive porphyrins (PAP) in malignant urothelium upon instillation of 5-aminolevulinic acid
(5-ALA) or its hexyl-derivative h-ALA. Fluorescence cystoscopy equipment has been developed with the aim to
compensate for the undesired distortion caused by the tissue optical properties by displaying the red fluorescence
simultaneously with the backscattered blue light. Many clinical studies proved a high sensitivity in detecting flat
carcinoma in situ and small papillary malignant tumours. As a result, recurrence rates were significantly decreased in
most studies. The limitation lies in a low specificity, caused by false positive findings at inflamed bladder wall. Optical
coherence tomography (OCT) is currently being investigated as a promising tool to overcome this limitation.
H-ALA-PDT (8 or 16 mM h-ALA in 50 ml instillation for 1-2 h, white light source, catheter applicator) has recently
been investigated in a phase I study. 17 patients were applied 100 J/cm2 (3 patients received incrementing doses of 25 -
50 - 100 J/cm2) during approx. 1 hour irradiation time in 3 sessions, 6 weeks apart. PDT was performed without any
technical complications. Complete photobleaching of the PpIX-fluorescence, as intended, could be achieved in 43 of 45
PDT-sessions receiving 100 J/cm2. The most prominent side effects were postoperative urgency and bladder pain, all
symptoms being more severe after 16 mM h-ALA. Preliminary evaluation shows complete response assessed at 3
months after the third PDT-session (i.e. 6 months after first treatment) in 9 of 12 patients. 2 of these patients were free of
recurrence until final follow-up at 84 weeks.
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