A retrospective study on ruthenium-106 and strontium-90 eye-plaques treatment for retinoblastoma: 16-years clinical experience.

Purpose: To retrospectively evaluate the efficacy of plaque brachytherapy for the treatment of retinoblastoma.

Methods: We retrospectively reviewed the clinical records of 163 patients (186 eyes, 333 tumors) treated with brachytherapy (¹⁰⁶Ru or ⁹⁰Sr plaques) for intraocular retinoblastoma between November 2007 and August 2023.

Results: Complete tumor control was achieved in 273 tumors (82%). Incomplete tumor control was observed in 44 tumors (13%). Thirteen tumors presented with tumor progression. Three tumors relapsed after brachytherapy. On multivariate statistical analysis apex dose ≤ 85 Gy (for ¹⁰⁶Ru) (p = 0.03), dark fundus pigmentation (p = 0.005) and intraarterial chemotherapy-brachytherapy period < 2 months (p = 0.001) demonstrated significant effect on brachytherapy insufficiency. Radiation-induced complications occurred in 62 eyes (33%). The most frequent complications were nonproliferative retinopathy (n = 39, 21%), optic neuropathy (n = 29, 16%) and vitreous hemorrhage (n = 29, 16%). Multivariate statistical analysis showed central localization (p = 0.005), tumor thickness > 2.7 mm (p = 0.04) and larger plaque diameter (>14 mm) (p = 0.035) to be the most significant variables for brachytherapy-associated complications. Eye retention was achieved in 91% of the treated eyes (n = 169). 17 eyes (9%) were enucleated. The reasons for enucleation were tumor recurrence or uncontrolled tumor growth (n = 7), anterior chamber involvement (n = 3), recurrent active vitreous seeding (n = 1), inability of adequate tumor monitoring due to opaque media (dense total vitreous hemorrhage or total retinal detachment) (n = 3), subatrophy of the eye with functional blindness (n = 3).

Conclusion: Overall, Beta-ray brachytherapy proved to be a highly effective method of retinoblastoma treatment with excellent local tumor control, eye preservation rate and acceptable incidence of curable radiation-induced complications.