Photodynamic therapy of prostate cancer by means of 5-aminolevulinic acid-induced protoporphyrin IX - in vivo experiments on the dunning rat tumor model.
OBJECTIVE
In order to expand the use of photodynamic therapy (PDT) in the treatment of prostate carcinoma (PCA), the aim of this study was to evaluate PDT by means of 5-aminolevulinic acid (5-ALA)-induced protoporphyrin IX (PPIX) in an in vivo tumor model.


METHODS
The model used was the Dunning R3327 tumor. First of all, the pharmacokinetics and the localization of PPIX were obtained using fluorescence measurement techniques. Thereafter, PDT using 150 mg 5-ALA/kg b.w. i.v. was performed by homogenous irradiation of the photosensitized tumor (diode laser lambda = 633 nm). The tumors were resected 2 days post-PDT and the extent of the necrosis was determined histopathologically.


RESULTS
The kinetics of PPIX fluorescence revealed a maximum intensity in the tumor tissue within 3 and 4.5 h post-application of 5-ALA. At this time, specific PPIX fluorescence could be localized selectively in the tumor cells. The PDT-induced necrosis (n = 18) was determined to be 94 +/- 12% (range 60-100%), while the necrosis of the controls (n = 12) differs significantly (p < 0.01), being less than 10%.


CONCLUSIONS
These first in vivo results demonstrate the effective potential of 5-ALA-mediated PDT on PCA in an animal model.
Zaak
Dirk
D
Department of Urology, Ludwig Maximilians University, Munich, Germany. Dirk.Zaak@uro.med.uni-muenchen.de
Sroka
Ronald
R
Stocker
Susanne
S
Bise
Karl
K
Lein
Michael
M
Höppner
Michael
M
Frimberger
Dominic
D
Schneede
Peter
P
Reich
Oliver
O
Kriegmair
Martin
M
Knüchel
Ruth
R
Baumgartner
Reinhold
R
Hofstetter
Alfons
A
D000622:Aminolevulinic Acid / Q000494:pharmacology; D000818:Animals; D004195:Disease Models, Animal; D008297:Male; D010778:Photochemotherapy; D011471:Prostatic Neoplasms / Q000188:drug therapy* / Q000473:pathology; D011524:Protoporphyrins; D051381:Rats
D011524:Protoporphyrins; D000622:Aminolevulinic Acid; C028025:protoporphyrin IX