Photodynamic therapy and photodynamic diagnosis using
photosensitizers have yet to be clinically employed for
hepatoma.
Mono-L-aspartyl chlorin e6, a
chlorin derivative with high
tumor affinity developed as a second-generation
photosensitizer, enables rapid
tumor detection after administration, without light-shielding. This study examined the potential of
photodynamic therapy, using this
photosensitizer, for
hepatoma in rabbits. VX2
tumor cells were transplanted into the liver of Japanese white rabbits, and the animals were administered 2.5 mg/kg of mono-L-aspartyl
chlorin 36 1 week later. Accumulation of
mono-L-aspartyl chlorin e6 in
hepatoma was observed over time with an epifluorescence stereoscope, and the efficacy of continuous
photodynamic therapy following photodynamic diagnosis was examined. A
diode laser system was used for treatment, and efficacy was examined in a control group and four other groups that were irradiated at different times following administration. Efficacy in suppressing
tumor growth,
tumor necrosis rates, and efficacy in suppressing pulmonary
metastasis were studied. For all these aspects, treatment was significantly more effective in the group irradiated 5 minutes after administration than in groups irradiated at later times. Liver function testing in all groups revealed no distinct disorders.
Photodynamic therapy with
mono-L-aspartyl chlorin e6 may be suitable for clinical use in
therapy for
hepatoma.