Visual acuity after Ruthenium 106 brachytherapy of choroidal melanomas

Abstract

To report on conservation of visual acuity after Ruthenium(106) (Ru-106) brachytherapy of choroidal melanoma. This study was a noncomparative interventional case series of 458 patients with choroidal melanoma treated at a single center between January 1993 and December 2001. The intervention consisted of Ru-106 brachytherapy delivering minimum scleral and apex doses of 300 Gy and 80 Gy, respectively, using a 15-mm or 20-mm plaque. For discrete, posterior tumors, the plaque was positioned eccentrically with its posterior edge aligned with the posterior tumor margin. To ensure correct plaque positioning, any overlying extraocular muscles were dis-inserted, and the locations of both tumor and plaque edges were confirmed by transillumination and indentation. The main outcome measures were conservation of vision of 20/40 or better, 20/200 or better, and Counting Fingers or better, according to baseline variables. The actuarial rate of conservation of 20/40 or better was 55% at 9 years, loss of such vision correlating with posterior tumor extension (p < 0.001), temporal tumor location (p = 0.001), increased tumor height (p = 0.01), and older age (p < 0.01) (Cox multivariate analysis). Similar analyses showed conservation of 20/200 or better in 57% of eyes at 9 years, loss correlating with reduced initial visual acuity (p < 0.001), posterior tumor extension (p < 0.001), and temporal tumor location (p = 0.006). Counting Fingers or better vision was conserved in 83% of patients at 9 years, loss correlating with increased tumor height (p < 0.0001). Local tumor recurrence occurred in 9 patients (actuarial rate, 3% at 9 years). Ruthenium(106) brachytherapy of posterior choroidal melanoma achieves good conservation of vision if the tumor does not extend close to the optic nerve or fovea.