Management of Iris Melanomas With ¹²⁵Iodine Plaque Radiotherapy

Purpose

To report the experience of the Princess Margaret Hospital/University Health Network with the treatment of iris melanoma (IM) with ¹²⁵Iodine plaque brachytherapy.

Design

Retrospective noncomparative case series.

Methods

All cases of IM submitted to ¹²⁵Iodine plaque radiotherapy were included. Patients' demographic, clinical, management, and follow-up data were reviewed. Outcome measures included rates of tumor control, eye preservation, systemic metastases, and brachytherapy-related complications.

Results

Fourteen IMs were included in the study. All patients had blue/green irises. Mean largest basal dimension and thickness were 7.1 ± 2.1 mm (range, 4.0 to 11.5 mm) and 2.2 ± 0.8 mm (range, 1.0 to 3.5 mm), respectively. Ten patients (71%) had seeding and 2 (14%) had glaucoma at presentation. Median follow-up was 26.6 ± 19.5 months (range, 6 to 72 months). Tumor control was achieved in 100% of the cases and no eye was enucleated because of radiation-induced complications. At last visit, all patients were alive and free of metastasis. Final visual acuity was the same as or better than before treatment in 9 patients (75%). Cataract was the most common complication (8; 75%), followed by persistent glaucoma (2; 17%) and anterior uveitis (1; 8%). No other significant complication was seen during the follow-up period.

Conclusions

Plaque radiotherapy is a safe and effective conservative treatment option for IM, although cataract is a common, yet treatable, complication. This treatment scheme circumvents an intraocular procedure and may avoid the dissemination of malignant cells, and provides a margin of safety in the treatment of clinically undetectable disease.