Plaque radiation therapy for malignant melanoma of the iris and ciliary body

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Abstract

PURPOSE: To report on plaque radiation therapy for malignant melanomas involving the iris and ciliary body.

METHODS: Twenty-two eyes (22 patients) with anterior uveal melanomas were treated with 103Pd ophthalmic plaque radiation therapy. Transillumination and ultrasonography were used to evaluate ciliary body involvement and posterior iris extension. Plaques were placed onto the cornea to treat the anterior tumor margins. The targeted-zone included the tumor and a 2 to 3 mm tumor-free margin. After plaque removal, patients were examined at 1 day, 7 days, 4 weeks, and then every 3 to 6 months thereafter. Systemic evaluations for possible metastatic disease were performed every 6 months.

RESULTS: After plaque radiation therapy, the melanomas decreased in thickness (mean 47%) in all 22 eyes, and no secondary enucleation was performed. One patient died of metastatic melanoma 5 years after radiation therapy. Despite anterior plaque placement that covered portions of the cornea, no epiphora, eyelash loss, or visually significant corneal opacities were noted. Whereas 15 of 21 phakic eyes (71%) developed secondary cataract, no eyes developed ischemic or neovascular radiation maculopathy. Four eyes were noted to have glaucoma before treatment, and two developed it after irradiation. Twenty of 22 eyes (91%) were within 2 lines of their pretreatment visual acuity. After radiation, the mean ± SD follow-up was 56 ± 34.4 months (range, 9 to 117 months).

CONCLUSIONS: Plaque radiotherapy of melanomas involving the iris and ciliary body resulted in excellent local control with preservation of vision. Although there was high incidence of secondary cataracts, 103Pd plaque radiation therapy resulted in no visually significant corneal opacity or radiation retinopathy.

Section snippets

Materials and methods

Patients were diagnosed as having uveal melanoma by clinical examination. Small iridociliary melanomas were watched for evidence of growth before treatment. All patients were told of the most common methods of treatment (observation for growth, iridectomy, iridocyclectomy, and enucleation) and were given the option for localized radiation therapy.

Informed consent was obtained after discussion of the findings, alternatives of treatment, potential benefits, and complications. This included a

Results

Plaque radiotherapy was administered to 22 eyes of 22 patients with melanoma involving the iris and ciliary body (Table 1). Tumors in this series had mean base diameters of 7.5 (width range, 4 to 12 mm) by 6.7 mm (length range, 4 to 12 mm) and average heights of 3.2 mm (range, 2 to 6.6 mm). No patient had a large-sized melanoma defined by a tumor height greater than 10 mm or a basal dimension greater than 16 mm (Table 1).

Tumor locations were defined as iris, iris and ciliary body, or were

Discussion

Ophthalmic plaque radiation therapy offers a method to treat iris and ciliary body tumors without the risks associated with intraocular surgery.7, 8, 12, 13, 14, 19 Ophthalmic plaques are sutured onto the episclera to cover the tumor’s base (plus 2 to 3 mm). Then ionizing radiation penetrates the intact selera and cornea before sterilizing the intraocular melanoma. Thus, the targeted zone includes the sclera beneath the tumor, the intraocular melanoma, and a margin for safety.

There have been

Conclusion

Ophthalmic plaque radiotherapy was used to treat 22 patients with uveal melanomas involving the iris and ciliary body. In this series, there was no failure of local control or secondary enucleation. In contrast to intraocular excision surgeries, there was no secondary retinal detachment, intraocular hemorrhage, infection, or potential for tumor seeding.

Radiation was associated with a high incidence of secondary cataract and no radiation maculopathy (within our follow-up period). Despite the

Acknowledgements

The author hereby acknowledges the clinical contributions of Drs Berson and Szechter in radiotherapy and dosimetry.

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This work was supported (in part) by The EyeCare Foundation, Inc, New York, New York.

1

Dr Finger is a paid consultant for Theragenics Corporation, Buford, Georgia, USA.

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