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Photoablation of ocular melanoma with a high-powered argon endolaser
G J Jaffe1, W F Mieler, J M Burke
1Department of Ophthalmology, Medical College of Wisconsin, Milwaukee.
Abstract:
We studied the use of a 15-W argon blue-green laser in the treatment of choroidal melanoma in a rabbit model. Greene melanoma cells were used to produce 2- to 4-mm thick tumors posteriorly in the suprachoroidal space in pigmented rabbits. Endophotocoagulation delivered through a 600-micron fiberoptic probe was performed to ablate the tumor tissue and a surrounding margin of normal tissue. A vitreous cutter was used simultaneously to remove liberated necrotic debris. The effect of the laser on tumor and normal ocular tissue was evaluated by light microscopy and the extent of the proliferative response by tritiated thymidine radioautography. Application of 100 to 400 pulses of laser energy using treatment parameters of 12 to 14 W of power and 0.1-s pulses resulted in complete ablation of melanoma tissue, overlying retina, and choroid. There was no substantial intraoperative or postoperative hemorrhage. Material liberated during the laser treatment was found to be nonviable. The effect of the laser on tissue appeared localized to within approximately 1.25 mm of the margin of the central lesion. The high-energy argon laser seems to offer a means of effectively ablating melanoma tissue via an internal resection approach.
Insights
A 15-W argon blue-green laser effectively ablated choroidal melanoma in rabbits. This endophotocoagulation technique offers a localized internal resection approach for ocular tumors.
Area of Science:
- Ophthalmology
- Oncology
- Laser Medicine
Background:
- Choroidal melanoma is a significant ocular malignancy.
- Current treatment options for choroidal melanoma have limitations.
- Novel therapeutic approaches are needed for effective tumor ablation.
Purpose of the Study:
- To evaluate the efficacy of a 15-W argon blue-green laser for treating choroidal melanoma in a rabbit model.
- To assess the safety and localization of laser energy delivery.
- To investigate the potential of endophotocoagulation as an internal resection method.
Main Methods:
- Greene melanoma cells were implanted in the suprachoroidal space of pigmented rabbits.
- Endophotocoagulation was performed using a 600-micron fiberoptic probe with a 15-W argon laser.
- Simultaneous removal of necrotic debris was achieved with a vitreous cutter.
- Histopathological analysis and radioautography were used for evaluation.
Main Results:
- Complete ablation of melanoma tissue, retina, and choroid was achieved with 12-14 W power and 0.1-s pulses.
- No significant intraoperative or postoperative hemorrhage was observed.
- Laser effects were localized to approximately 1.25 mm from the lesion margin.
- Liberated necrotic material was nonviable.
Conclusions:
- High-energy argon laser endophotocoagulation is effective for ablating choroidal melanoma.
- This internal resection approach demonstrates good tumor control and localized tissue effects.
- The argon laser shows promise as a minimally invasive treatment for ocular melanoma.