Prognosis of choroidal melanoma and the result of ruthenium brachytherapy combined with transpupillary thermotherapy in Korean patients

Background/aims To evaluate the clinical features and prognosis of choroidal melanoma in Korean patients and the results of treatment with ruthenium (Ru) 106 plaque brachytherapy. Methods The medical charts of 111 patients diagnosed with choroidal melanoma who underwent Ru brachytherapy with trans-pupillary thermotherapy or local resection (61 patients) or who underwent other treatments (26 primary enucleations, 22 λ-knife radiotherapies and two lamellar sclerouvectomies) were reviewed retrospectively. Results The mean largest basal diameter (LBD) was 11.4±3.2 mm and the mean apical height was 7.8±2.9 mm. Compared with the collaborative ocular melanoma study, mean tumour height was skewed toward higher values (6.2 vs 4.8 in medium tumours, p<0.0001; 10.9 vs 9.5 mm in large tumours, p=0.034) and the LBD in large tumours was skewed toward smaller values (13.6 vs 17.3, p<0.0001). The estimated 5-year metastasis-free rate was 73.9% and the disease-specific survival rate was 84.6%. For the 61 patients that were treated with Ru brachytherapy, the 5-year metastasis-free and disease-specific survival rates were 79.0% and 87.7%, respectively, and the 5-year incidence of enucleation was 25.4%. The mean tumour regression at 6, 12 and 18 months after brachytherapy was 80.2%, 73.1% and 69.2%, respectively. Conclusions Choroidal melanomas in Korean patients tend to grow vertically with a relatively large apical height and a small LBD. The prognosis of choroidal melanomas overall as well as prognosis after Ru brachytherapy were similar to those seen in previous studies with Caucasian patients. The enucleation rate after brachytherapy seems to be higher in Korean patients, for which a greater initial tumour height seems to be partly responsible.