New Zealand experience of I¹²⁵ brachytherapy for choroidal melanoma

Abstract

Patient outcomes following brachytherapy were excellent with a high percentage of patients retaining mobility vision. Development of complications was related to the tumour location and dose to non-tumour structures.

Treatment of radiation retinopathy following plaque brachytherapy for choroidal melanoma

“…However, the ensuing radiation retinopathy results in frequent complications that compromise posttreatment vision. Radiation retinopathy has been reported to occur in 10-63% of postplaque eyes, with higher rates associated with larger tumors or increased radiation dosages or both [4][5][6][7][8][9][10][11]. In a recent Collaborative Ocular Melanoma Study of postplaque eyes that were enucleated for treatment failure, 55% of eyes demonstrated evidence of vascular abnormalities related to radiation retinopathy [12].…”

Ocular complications following I-125 brachytherapy for choroidal melanoma

“…However, in the studies with I-125 brachytherapy, few reports mention scleral atrophy or necrosis as a complication. Stack et al 14 documented that none of their 84 patients developed scleral necrosis after I-125 brachytherapy.…”

“…Higher radiation dose and tumours with thickness greater than 4 mm increase the risk for radiation maculopathy. 14 Stack et al 14 found a 63% risk for radiation maculopathy if the dose to the macula exceeded 90 Gy. A decreased distance to the foveola as well as male gender have also been associated with a decreased time to maculopathy.…”

Management of Radiation Maculopathy

“…The major modifiable risk factor for development of radiation maculopathy is the total dose of radiation to the macula [18]. Newer designs/techniques of delivering radiation should be explored [6,7,8,13,19,20]. The other option of attenuating intraocular radiation by temporarily filling the vitreous cavity with silicone oil is also under investigation [21].…”

“…The risk of radiation maculopathy is increased in the presence of comorbidities such as diabetes and prior chemotherapy [6,7,8]. In addition, several modifiable radiation factors such as the type of radiation delivery method (teletherapy vs. brachytherapy), fractionation, type of radiation isotope used for brachytherapy (ruthenium-106 vs. iodine-125) and the total dose delivered to the macula also significantly influence the risk of developing radiation maculopathy [9].…”