Purpose: Despite the long history of COMS (Collaborative Ocular Melanoma Study) eye plaques, limited consensus for dose thresholds exists for the optic disc and macula. A retrospective study was conducted to identify a correlation between complications and doses to optic structures for ocular melanoma patients. The primary objective of this work was to define dose-side effect relationships and identify dose thresholds for radiation retinopathy, vision decline, blindness, and cataract formation.
Methods: A cohort of 52 patients treated with COMS plaques at our institution between 2004-2019, with adequate follow up data, were used in a single institution retrospective study. Patient demographics, dosimetry, and clinical outcomes were recorded. A univariate analysis and relative risk estimates were performed to analyze dose-side effect relationships for the optic disc, lens, and macula. A logistic regression was performed to identify dose percentiles for retinopathy, vision decline, blindness, and cataracts.
Results: Doses to the optic disc and macula had significant relationships (p≤0.05) with incidence of radiation retinopathy, moderate vision decline (5 or more Snellen lines), and onset of blindness. Moreover, significant (p≤0.05) relative risk estimates exist for radiation retinopathy, vision decline, and blindness for doses greater than 35 Gy to the optic disc, and 55 Gy to the macula. Finally, a macula dose of 55 Gy will result in less than 13% of patients experiencing radiation retinopathy or vision loss. Optic disc doses of 24 and 33 Gy would result in less than 13% of patients experiencing retinopathy or vision loss, respectively.
Conclusion: Based on the results of the study, it can be concluded that dose-effect relationships exist for the optic disc and macula with respect to radiation retinopathy, vision loss, blindness. To improve a patient’s quality of life beyond treatment, further work is needed to expand upon dose reduction strategies for patients undergoing eye plaque brachytherapy.