Prognostic factors for surgical treatment of radiation-induced scleral necrosis after brachytherapy for uveal melanoma

Abstract Objectives: Radiation-induced scleral necrosis (RISN) is a rare complication of brachytherapy for uveal melanoma, and may require surgical treatment in selected cases. We aimed to identify the prognostic factors for RISN treatment. Design: Retrospective, single-center, observational case series Methods: All patients with brachytherapy for uveal melanoma treated at our institution between 01/1999 and 12/2016 who developed RISN were followed until 02/2021. Various parameters were evaluated through univariable and multivariable Cox regression analysis. The surgical intervention due to RISN was the principal outcome event of this study. Results: Of 115 patients in the final cohort, 51 individuals (44.3%) underwent RISN treatment (conjunctival revision [n = 2], patching [n = 46] or enucleation [n = 3]) at median 1.80 months after RISN occurrence. Significant RISN characteristics were summarized into a novel RISN severity scale – Grade I: largest diameter ≤ 5mm and no progression; Grade II: largest diameter > 5mm or any progression during the follow-up; Grade III: presence of uveal prolapse; and Grade IV: leakage through open eyewall perforation. In the multivariable analysis, the RISN severity scale (aHR = 2.37 per grade increase, p = 0.005) and the time between brachytherapy and RISN occurrence (< 15 months, aHR = 6.33, p < 0.0001) were independently associated with the study endpoint. The RISN severity scale showed high diagnostic accuracy for prediction of RISN treatment (AUC = 0.869). Conclusions: In our series, about the half of RISN cases underwent surgical treatment. The presented novel severity scale for RISN might become a helpful tool for clinical management of individuals with RISN. We recommend external validation of the diagnostic accuracy of the presented scale.