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Unsöld, E. ; Baumgartner, R. ; Beyer, W.F. ; Jocham, D. ; Stepp, H.G.

Fluorescene detection and photodynamic treatment of photosensitized tumours in special consideration of urology.

Lasers Med. Sci. 5, 207-212 (1990)
DOI
Open Access Green möglich sobald Postprint bei der ZB eingereicht worden ist.
Most methods of modern laser tumour therapy are physically based on the conversion of light to heat. Recently tumours have also been treated using ionizing processes for tissue ablation. Photodynamic laser therapy (PDT), however, involves light-induced non-thermal biochemical processes and the use of a photosensitizer. Several drugs are known to be stored selectively in tumours after systemic application. This transient marking can be used for diagnostik and therapeutic procedures. The marker most commonly used is dihaematoporphyrin ether/ester (DHE) intravenously injected at doses of 0.2-3.0 mg/kg bodyweight for diagnosis and therapy, respectively. The corresponding clearance intervals after injection of DHE range from 3-48 h to 25-75 h. Detection of photosensitized tumours might offer great advantages. The highly sensitive two-wavelenght laser excitation method with computerized fluorescene imaging recently has been transferred to the hospital for clinical tests. Photoinduced production of singlet oxygen is claimed to be the initial process which leads to later tumour destruction and therapy. PDT has been applied to 20 patients suffering from superficial tumours (TIS GII-III) recurred after application of other treatments. The results after PDT were evaluated by three-monthly check-ups (endoscopy, cytology, bladder mapping, renal ultrasonography) as well as by computed tomography (CT) examination at 8-13 month intervals. In six patients treated by PDT no tumour recurrence has been found over the whole observation period of up to 5 years. Four patients have remained free of tumour (12 and 14 months) after repeated transurethral reserction (TUR) and Nd-YAG laser therapy following PDT. Due to an initial application of insufficient irradiation four patients required a second PDT. In one patient a cirumscribed dysplasia appeared at the left ostium 26 months following PDT and was treated successfully by means of thermal Nd-YAG laser irradiation following TUR. In six patients slight mucosal atypia persisted for a period of at least 2.5 years. One cystectomy had to be performed because of bladder shrinkage. The dissected bladder, however, was free of tumour. These preliminary results suggest that PDT is justified in patients who are in a worst-case situation with cystectomy recommended in case of recurrent superficial TIS bladder carcinoma and indicate the future potential of photodynamic therapy of tumours. Homogenous irradiation of the area to be treated and a reliable light dosimetry are perequisites for an effective tumour therapy. Standard instruments for a routine application do not exist, but are under development.
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Publikationstyp Artikel: Journalartikel
Dokumenttyp Wissenschaftlicher Artikel
Korrespondenzautor
ISSN (print) / ISBN 0268-8921
e-ISSN 1435-604x
Zeitschrift Lasers in Medical Science
Quellenangaben Band: 5, Heft: 2, Seiten: 207-212 Artikelnummer: , Supplement: ,
Verlag Springer
Nichtpatentliteratur Publikationen
Begutachtungsstatus Peer reviewed
Institut(e) Laser laboratory (ZLL)