Long-term follow-up after uveal melanoma charged particle therapy.

PURPOSE: To examine the results of helium ion irradiation in 218 uveal melanoma patients treated more than 10 years ago.
METHODS: Retrospective review of 218 eyes treated with helium ion radiation for uveal melanoma between 1978 and 1984. Several parametric and non-parametric statistical analysis techniques were used.
RESULTS: In 218 eyes treated with helium ion radiation for uveal melanoma, the mean dimension for largest basal diameter was 11.9 mm (range 5 mm to 24 mm). The mean tumor thickness was 6.7 mm (range 1.3 mm to 14.2 mm). Following helium ion radiation 208 (95.4%) of 218 eyes had local tumor control. At 10 years after radiation 46 (22.4%) of 218 eyes were enucleated; the majority (37 of 46) of enucleations were due to anterior ocular segment complications. At 10 years after radiation 102 (46.8%) of the 218 patients were dead; half had non-tumor related deaths and 51 died from metastatic melanoma. Best corrected visual acuity after radiation was > or = 20/40 in 21 of 93 eyes of patients that were alive and retained their eyes 10 or more years after treatment. In patients with tumors that were less than 6 mm in height and more than 3 mm away from the nerve or the fovea, 13 of 18 (72%) retained > or = 20/40. In contrast, only 11% of the patients with either thicker tumors or those close to the nerve or fovea retained that level of acuity. The actuarial enucleation rate at 5 years was 17.2% (2.7% S.E.) and at 10 years this was 22.4% (3.1% S.E). The recurrence tumor control rate at both 5 and 10 years was 5.3% (S.E 1.7%).
CONCLUSIONS: Helium ion radiation of uveal melanoma is associated with good local tumor control and reasonable retention of the treated eye 10 years after treatment. In tumors that are less than 6 mm in thickness and greater than 3 mm from the optic nerve and fovea, many retain excellent vision. Approximately one-half of the deaths 10 years after treatment were due to non-tumor-related causes.