Plaque radiotherapy for juxtapapillary choroidal melanoma: tumor control in 650 consecutive cases

Abstract

Purpose: To evaluate treatment of juxtapapillary choroidal melanoma with plaque radiotherapy and to investigate the role of supplemental transpupillary thermotherapy (TTT).

Design: Retrospective, comparative case series.

Participants: We included 650 consecutive eyes with juxtapapillary choroidal melanoma within 1 mm of the optic disc.

Methods: Eyes with juxtapapillary choroidal melanoma receiving plaque radiotherapy over a 31-year period from October 1974 to November 2005 were included in the study. The TTT and no TTT groups were analyzed separately and compared.

Main outcome measures: Local tumor control, metastasis, and tumor-related mortality.

Results: The median basal tumor diameter was 10 mm (range, 1.5-21) and median thickness was 3.5 mm (range, 0.5-14.8). In 481 eyes (74%), the tumor was directly adjacent to the optic disc and in 169 eyes (26%) the posterior tumor margin was between 0.1 and 1.0 mm from the optic disc. The circumpapillary extent of the tumor was <4 clock-hours in 321 eyes (50%), 4-8 clock-hours in 250 eyes (38%), and >8 clock-hours in 79 eyes (12%). Plaque radiotherapy using iodine-125 in 616 eyes (95%), cobalt-60 in 19 eyes (3%), iridium-192 in 12 eyes (2%), and ruthenium-106 in 3 eyes (<1%) delivered a median radiation dose of 8000 cGy (range, 3600-15 500) to the tumor apex and adjunctive TTT was used in 307 eyes (56%). Kaplan-Meier estimates for tumor recurrence, metastasis, and death were 14%, 11%, and 4% at 5 years and 21%, 24%, and 9% at 10 years, respectively. Eyes treated with additional TTT showed slight (statistically nonsignificant) reduction in recurrence and metastasis. Using multivariable analysis, factors predictive of tumor recurrence included foveolar tumor requiring TTT (hazard ratio, 5.07; P<0.001) and greater tumor thickness (hazard ratio, 1.29 per mm increase; P<0.001). Factors predictive of metastasis included greater tumor base (hazard ratio, 1.21 per mm increase; P<0.001) and increasing intraocular pressure (hazard ratio, 1.11 per mmHg increase; P = 0.020).

Conclusions: Plaque radiotherapy for juxtapapillary melanoma provides local tumor control in approximately 80% of eyes at 10 years. In subjects who received TTT, there was slight but nonsignificant improved local tumor control and lower metastatic rate.