98th Annual Meeting DOG 2000

P 694

Endovaporisation of uveal melanoma – preliminary in-vitro investigation

G. Langmann, K. Müllner, R. Kleinert, J. Faulborn

Problem: Small and medium sized tumors can be destroyed by different methods of radiation therapy with a minimum rate of sequelae. Globe preserving therapy in case of large tumors is limited due to a high rate of complications. The aim of our study was to investigate tumor vaporisation of a large uveal melanoma by means of a KTB laser.

Material and method: Vaporization of the tumor was performed with a KTP (Kalium-Titanium-Potassium) laser used at our hospital in endoscopic lacrimal surgery (wave length: 532 nm, energy: 0,5 -10 Watt) This laser with a working diameter of 0,3 mm vaporised nearly all of the melanoma with a size of 16 x 12 x 11 mm within a few minutes, the rest of the tumor was left for histopathological investigation.

Results: Using energy between 3-8 Watts the tumor was transformed into steam. In histopathological investigation the vital tumor was mainly com-posed of epitheloid cells and didn’t show any sign of spontaneous tumor necrosis. At the impact of KPT laser the surface showed superficial necrosis, marginal parts of the laser crater were carbonized.

Conclusion: KTP laser can vaporise uveal melanoma under air and seems to be suitable for the endovaporisation of large uveal melanomas. Its wave length of 532 nm induces an optimum interaction between the KPT laser and oxyhaemoglobin thus preventing bleeding and dissemination of tumor cells during treatment. In order to adjust the lacrimal probe for endovaporisation of intraocular tumors we now intend to combine the probe with a suction device to remove the steam.

Univeritäts-Augenklinik, Auenbruggerplatz 4, A- 8036 Graz, Österreich