Plaque radiotherapy may offer long-term control of iris melanoma

Issue: August 25, 2012

Iodine-125 plaque radiotherapy proved effective in long-term management of residual or recurrent iris melanoma after surgical resection, a study found.

Perspective from Carol L. Shields, MD

“Two important considerations regarding local tumor resection include the concern for residual tumor and the potential for recurrent tumor,” the study authors said. “The goal of surgery is to achieve complete removal with clinical and histopathologic tumor-free margins. Residual viable tumor can lead to local recurrence and pose a risk for metastasis.”

The retrospective, nonrandomized interventional case series included 32 eyes of 32 patients (mean age: 53 years) who underwent iodine-125 plaque radiotherapy for residual or recurrent iris melanoma after surgical resection. Iris melanoma was residual in 12 patients and recurrent in 20 patients. The median interval between surgical resection and plaque radiotherapy was 12 months.

Snellen visual acuity at presentation was 20/20 to 20/50 in 84% of eyes, 20/60 to 20/150 in 9% of eyes, and 20/200 or worse in 6%. Mean follow-up after plaque radiotherapy was 42 months.

Six years after radiotherapy, residual or recurrent iris melanoma control was achieved in 87% of eyes; 13% of eyes underwent enucleation. Also at 6 years, metastasis occurred in 3% of eyes.

Final visual acuity was 20/20 to 20/50 in 34% of eyes, 20/60 to 20/150 in 25% of eyes, and 20/200 or worse in 28%.

Limitations of the study included inadequate follow-up of many patients and a lack of internal controls, the authors said.

Perspective

Carol L. Shields, MD

Iris melanoma is most often managed by microsurgical resection with an attempt to achieve 1 to 2 mm of clear margins. When performing resection, there are numerous variables that challenge clean margins, including the amount of uvea that can be safely removed, reduced visibility of tumor margins through the softened cornea with open eye, dispersed hemorrhage within the aqueous, and fear of surgical complications including profound hemorrhage, lens dislocation, cataract formation, and retinal detachment. Despite best efforts, the tumor that appears completely resected could have microscopic residua left in the eye post-resection.

Plaque radiotherapy is a method to control microscopic or macroscopic residua or recurrence following resection of melanoma. This technique is extremely valuable for salvage of the eye. Despite the radiation dose delivery through clear cornea, the eye tolerates this therapy remarkably well with few complications.

Carol L. Shields, MD

Oncology Service, Wills Eye Institute,

Philadelphia

Disclosures: Shields has no relevant financial disclosures.

Published by:

Sources/Disclosures

Collapse

Source:

Ophthalmology. 2012;119(4):838-842.