Object: The authors compared the results of gamma knife radiosurgery in patients with uveal melanoma who underwent high-dose (treated from 1992-1995) and low-dose irradiation (treated from 1996-2002).
Methods: Thirty-one patients with uveal melanomas were treated with a mean margin dose of 52.1 Gy (high dose) and 33 with a mean dose of 41.5 Gy (low dose), and results were compared between groups. The technical procedure was the same in each group except for radiation dose. In the low-dose group, complete tumor regression (scar formation) occurred in 12% and in the high-dose group in 26%. Partial regression (reduction of the tumor prominence between 50 and 80%) occurred in 81% of the low-dose group and in 58% of the high-dose group. Neovascular glaucoma as a severe complication developed in 9% of the low-dose group and in 48% of the high-dose group.
Conclusions: Reduction of the margin dose from 52.1 to 41.5 Gy appears to achieve the same rate of tumor regression but is associated with a lower rate of severe side effects such as neovascular glaucoma. The follow-up period in the low-dose group, however, was much shorter.