Silicone Oil and Iodine-125 Brachytherapy for Uveal Melanoma in High-Risk Patients

Abstract

PurposeSilicone oil a burgeoning adjuvant in the treatment of uveal melanoma where it is used for tissue protection during I-125 brachytherapy. While risk factors in the development of radiation retinopathy (RR) have been identified, treatment modulation for high-risk patients has largely been overlooked. We seek to expand the literature on this subject by reporting outcomes of I-125 brachytherapy with silicone oil in a high-risk population in the community setting.MethodsFive patients with uveal melanoma and at least one risk factor for RR development underwent iodine-125 (I-125) plaque brachytherapy with concurrent pars plana vitrectomy (PPV), silicone oil administration, and fine needle aspiration biopsy (FNAB). Plaque and silicone oil removal were performed after seven days. Minimum follow-up was 12 months.ResultsFollow-up ranged from 12 to 56 months. Macular radiation doses ranged from 12.55 to 141.5 Gy; the two eyes with the largest doses developed RR at 34 and 15 months as well as neovascular glaucoma (NVG). Surgical complications included one rhegmatogenous retinal detachment (RD) and an intra-operative vitreous hemorrhage with post-operative hyphema requiring additional intervention.ConclusionRR may be attenuated by silicone oil administration in patients with some risk factors. In tumors farther from the macula, this benefit is more readily apparent. Tumors located more posteriorly may not benefit from silicone oil administration considering postoperative complications and operating time. Patient demographics, tumor characteristics, and anticipated macular radiation dosage may help determine which patients can benefit from silicone oil and identify patient risks for adverse outcomes.

Vitreoretinal Surgery in the Prevention and Treatment of Toxic Tumour Syndrome in Uveal Melanoma: A Systematic Review

“…This practice is based on the evidence of an attenuating effect of silicone oil 1000-cSt, resulting in a reduction of 50–60% of radiation exposure of healthy ocular tissue to side radiation from iodine-125 brachytherapy [ 20 ]. Lyons et al [ 21 ] reported 2 cases of RR and 1 case of NVG that was eventually enucleated. BCVA was particularly well preserved in the cohort.…”

Deterioration of Visual Acuity after Brachytherapy and Proton Therapy of Uveal Melanoma, and Methods of Counteracting This Complication Based on Recent Publications

“…Bearing in mind the limitations mentioned above and comparing the research studies on visual acuity deterioration after Ru-106 brachytherapy, I-125 brachytherapy and proton beam therapy of uveal melanoma published at the turn of the 20th and 21st centuries [ 3 , 30 , 55 , 56 ] and in the last 4 years [ 9 , 11 , 21 , 31 , 33 , 34 , 35 , 37 , 38 , 39 , 41 , 42 , 44 , 49 , 50 , 51 ], we can conclude that the degree of visual impairment is comparable. Considering the extremely dynamic development of medicine and widely understood technology, one would like to achieve greater progress in this field.…”

“…A method of protecting healthy tissues in the form of replacing the vitreous body with silicone oil proposed by Yang et al, Lyons et al and other researchers suggests that further searching for substances that protect against radiation even better and, at the same time, are safer for the eye is needed [ 47 , 48 , 49 , 50 ]. However, serious potential complications associated with the vitrectomy procedure should be borne in mind when considering such a method.…”

“…Researchers connected this to a much lower dose of radiation received by the macula, which resulted not only from distance, but was also due to the protective properties of silicone oil. In the case of tumors located in the area of the macula, the possibilities of silicone oil cannot be utilized [ 50 ].…”