COMS IRIS plaque radiotherapy safe, effective against melanoma

The use of Collaborative Ocular Melanoma Study (COMS) IRIS plaques is an effective treatment approach to iris, iridociliary, and ciliary body melanoma, a recent study has found.

COMS IRIS plaques yield modes improvements in visual acuity (VA) while suppressing local tumour recurrence, systemic metastasis, enucleation, and side effects from radiation.

The retrospective study included 22 patients (mean age at diagnosis 59 years, 64 percent women) with iris melanoma treated with COMS IRIS plaque radiotherapy. At presentation, mean Snellen VA was 20/30, with 82 percent of affected eyes having mean VA of ≥20/40. Mean baseline intraocular pressure (IOP) was 15 mm Hg and two patients were on IOP-lowering medication prior to enrolment.

The average prescription depth for COMS IRIS plaques was 5 mm. Patients were treated for a mean total duration of 95 hours, over which time the average total radiation dose delivered to the tumour apex was 135.5 Gy.

Over a mean follow-up time of 51 months, 14 eyes (64 percent) had Snellen VA ≥20/40 while IOP rose to 18 mm Hg; 11 patients required IOP-lowering medications. Mean tumour basal diameter and thickness was 4.1 and 1.4 mm, respectively, after treatment.

Local recurrence was detected in only two patients (9 percent), which occurred after 15 and 69 months after radiotherapy; both necessitated enucleation. Kaplan-Meier analysis estimated that the 3-year risk of local recurrence was 7 percent. Systemic metastasis did not occur.

In terms of side effects, 77 percent of patients experienced progression or development of cataract. Other complications included dry eye (22.7 percent), neovascularization of the iris (4.5 percent), and neovascular glaucoma (4.5 percent).

“These findings suggest [that] radiotherapy with COMS IRIS plaques is safe and effective for treatment of iris melanoma,” the researchers said.