Abstract
Purpose: :
To report a two-stage approach for the treatment of iris melanomas not amenable to surgical excision or brachytherapy alone.
Methods: :
We reviewed eight consecutive patients with iris melanomas diffusely invading the anterior chamber that were treated with iridectomy (with or without anterior cyclectomy) followed by Iodine-125 plaque brachytherapy. Data recorded from the patients’ medical records included: age at diagnosis, gender, race, presenting complaint, pre-operative and final best-corrected Snellen visual acuity, pre-operative and final intraocular pressure, surgical approach and dosimetry. We also collected the following tumor-specific data: tumor size, iris location, percentage of anterior chamber angle involvement, presence of tumor at the posterior surgical margin, histopathology, local recurrence and metastasis.
Results: :
All eight patients (5 males, median age 62) had iris melanomas involving greater than 25% of the trabecular meshwork. Median follow-up was 24 months (range, 2.1- 44.7 mos). Six tumors invaded the anterior ciliary body, 3 were adherent to corneal endothelium and one involved sclera. The presenting complaint(s) included at least one of the following: a newly discovered iris lesion (n=4), blurry vision (n=3), ocular pain (n=2) and tearing (n=1). Four patients were asymptomatic at diagnosis. On histopathology, the melanomas were classified as spindle cell variants (25%) and mixed-cell variants (75%). All specimens were positive for tumor cells at the posterior surgical margin. Mean brachytherapy dose was 82.5 Gy (range, 80.6-85.1 Gy) to a depth of 5 mm over 7 days with an effective dose rate of 49.0 cGy/hour. There was no significant change in visual acuity or intraocular pressure after surgery. No patient lost more than 3 lines of Snellen visual acuity at last follow-up. There was no disease recurrence or metastasis in any patient during the follow-up period. Complications were limited to sectoral cataract in 1 patient and mild dry eye symptoms in 2 patients.
Conclusions: :
Combined surgical excision and brachytherapy provides effective local control for iris melanomas with diffuse anterior chamber involvement. This dual treatment approach can preserve visual acuity and physiologic intraocular pressure with minimal side effects.
Keywords: melanoma • iris • radiation therapy