Photodynamic therapy of pigmented choroidal melanomas using a liposomal preparation of benzoporphyrin derivative
L. H. Young, M. A. Howard, L. K. Hu, R. Y. Kim and E. S. Gragoudas
Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, USA.
OBJECTIVE: To evaluate the effectiveness of photodynamic therapy of
pigmented choroidal melanoma using a liposomal preparation of
benzoporphyrin derivative monoacid (BPD), verteporfin. DESIGN: Pigmented
choroidal melanomas were established in 25 New Zealand albino rabbit eyes.
The animals were treated with daily injections of cyclosporine, and tumor
growth was monitored with funduscopic examination and ultrasonography.
Fifteen minutes after intravenous injection of BPD (2 mg/kg), the tumors
were irradiated at 692 nm through an argon-pumped dye laser with the
delivered fluence ranging between 40 and 150 J/cm2. Control animals were
treated with light only, photosensitizer only, or observation only. Tumor
growth was monitored by indirect ophthalmoscopy, fundus photography,
fluorescein angiography, and ultrasonography. Histologic examination was
performed. RESULTS: Eighteen tumor-bearing rabbits were treated with light
and BPD; 16 were followed up for 1 month, and two were killed immediately
for histologic examination. Tumors regressed in all eyes treated with 60
J/cm2 or more. With fluence of 40 J/cm2, tumor regrowth was observed in one
animal within 10 days of treatment. In the three control groups, all
animals showed continuous tumor growth. Histologic examination of the eyes
treated with photosensitizer and light immediately after treatment showed
prominent vascular occlusion throughout the full thickness of the tumor.
One month after treatment, tumor necrosis and infiltration of mononuclear
cells and pigment-laden macrophages were the predominant findings.
CONCLUSIONS: Photodynamic therapy with BPD may have a role in the treatment
of pigmented choroidal melanomas.
