[Dose-volume histogram regression analysis of uveal melanomas after single fraction gamma knife radiosurgery]

To evaluate tumor regression and sequelae in 30 uveal melanomas treated with Gamma Knife radiosurgery between 1992 and 1995 at the Gamma Knife center in Graz.

A total of 30 uveal and ciliary body melanomas were treated with a single fraction of the Gamma Knife. The mean marginal dose was 52.1 Gy, (median 50 Gy). Of the tumors, 15 were large (higher than 8 mm), 14 were medium sized (3-8 mm) and one was a small melanoma (<3 mm). Among them were 6 juxtapapillary, 10 (juxta-) maculary melanomas, 5 tumors located in the midperiphery and 9 ciliary body melanomas.

Dose-volume histogram analysis.

After a maximum follow up of 9 years and 7 months, 8 tumors regressed into a scar, 17 tumors into a residual prominence between 50% and 80% of the initial tumor height, 3 tumors showed no change and in 2 patients recurrence was obvious. Sequelae were classified as mild (in 3 patients), moderate (3), severe (5) and very severe (19).

Significant factors for the development of severe sequelae were the tumor volume and the marginal dose, the mean dose proved to be more important than the marginal dose and the irradiated volume more important than the selective critical dose.