To assess the efficacy and prognosis of selective transpupillary thermotherapy (TTT) adjunctive to I¹²⁵ plaque radiotherapy (PRT) for choroidal melanoma.

The study retrospectively analyzed 601 patients (601 eyes) treated with I¹²⁵ PRT for choroidal melanoma, collected from January 2008 to March 2019 at the Ophthalmology Department of Tongren Hospital, Capital Medical University. Among them, there were 306 males (306 eyes) and 295 females (295 eyes) with an average age of (46.6±11.9) years (ranged from 13 to 85 years). All patients underwent indirect ophthalmoscopy, fundus fluorescence angiography (FFA), indocyanine green choroidal angiography (ICGA), color Doppler ultrasound, liver function test, and abdominal ultrasound before and after PRT. Supplemental TTT was given to the tissue with tumor vasculature residue after PRT. Gender, age, pre-treatment intraocular pressure, tumor shape, tumor height, tumor maximum basal diameter, disc involvement, vitreous hemorrhage, subretinal fluid, and prognosis (enucleation, metastasis, deaths) were recorded. The age, tumor height, and maximum basal diameter, in accord with normal distribution, were represented by (±s) and compared by independent sample t-test. The time of follow-up, time to enucleation, metastasis, and death did not conform to a normal distribution and were described by median and quartiles. The gender, tumor shape, disc involvement, subretinal fluid, vitreous hemorrhage and prognosis (enucleation, metastasis, deaths) were described by cases and percentages. Among them, the differences of gender, tumor shape, disc involvement, cases with subretinal fluid and vitreous hemorrhage before and after treatment were compared by the chi-square or exact probability test; the cumulative probabilities of enucleation, metastasis, and attributed death were analyzed by Kaplan-Meier survival analysis, and risk factors were analyzed using Cox proportional hazards model.

There were 60 cases (60 eyes) of 601 cases (601 eyes) with the residual tumor vasculature and treated by supplemental TTT, accounting for 9.98%. One session was required in 51 cases (51 eyes), accounting for 85.0%. The mean age of the patients with and without residual tumor vessels were (42.3±12.1) and (47.1±11.8) years with statistical significance, respectively (t=3.00, P<0.05). The 3 and 5-year enucleation rates of the 60 cases (60 eyes) treated by supplemental TTT were 6.7% (95%CI: 2.6 to 6.8) and 18.9%(95%CI: 10.9 to 31.6), respectively. The 3 and 5-year metastasis rates were 3.3% (95%CI: 0.8 to 12.7) and 10.2% (95%CI: 7.7 to 21.3), respectively. The 3-year and 5-year attributable mortality rates were 1.7% (95%CI: 0.2 to 11.2) and 6.7% (95%CI: 2.6 to 16.9), respectively. In multivariate analysis, the tumor largest basal diameter and optic disc involvement were risk factors for enucleation (HR=1.22, 4.35; 95%CI: 1.11 to 1.34, 1.84 to 10.23; χ²=4.14, 3.36; P<0.05). Tumor maximum basal diameter and subretinal fluid were risk factors for metastasis (HR=1.26, 6.31; 95%CI: 1.16 to 1.37, 1.94 to 20.51; χ²=5.44, 3.06; P<0.05). The tumor largest basal diameter, age, and intraocular pressure were risk factors for attributable death (HR=1.23, 1.52, 1.10; 95%CI: 1.11 to 1.35, 1.20 to 1.91, 1.02 to 1.19; χ²=4.15, 3.53, 2.42; P<0.05).

The tumor vasculature residue after PRT can be evaluated by FFA accompanied by ICGA. The supplemental TTT could be used to treat the tumor residue of the affected eyes. The tumor maximum basal diameter is a notable risk factor for poor prognosis, which should be paid attention.