Ruthenium-106 (106Ru) plaque brachytherapy as salvage treatment for retinoblastoma following intravenous chemotherapy.

Purpose: To describe the clinical presentation and treatment outcomes of patients undergoing Ruthenium-106 (¹⁰⁶Ru) plaque brachytherapy as salvage treatment for retinoblastoma (RB) following intravenous chemotherapy (IVC).

Methods: Retrospective chart review of 44 eyes of 42 patients. The indications for plaque brachytherapy included solid tumor recurrence (n=20; 45%), solid tumor residual (n=16; 36%), new subretinal seeds (n=5; 12%), and new solid tumor (n=3; 7%).

Results: The median age at the presentation was 12 months (range, 3-72 months). Based on ICRB classification, 8 (18%), 8 (18%), 16 (36%), and 5 (12%) tumors belonged to Groups B, C, D, and E, respectively. A median interval of 5 months (range 3-21 months) was noted between the last IVC cycle and plaque brachytherapy. The mean tumor height was four mm (range, 1.5-6 mm). All patients were treated with ¹⁰⁶Ru plaque (round or notch) with a median total dose of 45 Gy (range, 40-55 Gy) delivered to the tumor apex. At a mean post plaque follow-up period of 28 months (median, 23 months; range, 3-132 months), tumor completely regressed in 25 eyes (56%). Tumor recurrence within the plaque site was noted in eight eyes (18%) associated with a type 2 regression pattern (75%). At the last follow-up, the globe salvage rate was 24 eyes (55%), while 2 patients (5%) died due to metastasis.

Conclusion: ¹⁰⁶RU plaque brachytherapy can be a useful salvage treatment for focal tumors (new or recurrent) following systemic IVC.