The Role of Eyewall Resection in Uveal Melanoma Management

Abstract

Eyewall resection involves the removal of the intact tumor through a large opening in the overlying sclera, if possible without damaging the adjacent retina. This term generally refers to the treatment of large choroidal and ciliary body tumors; the resection of iris and ciliary body melanomas is usually described as iridectomy or iridocyclectomy. This chapter focuses on transscleral choroidectomy and cyclochoroidectomy. Several authors have written about eyewall resection of choroidal tumors.1-6 However, this form of treatment plays a limited role in the management of choroidal melanoma, being performed in a small number of centers and then only when primary radiotherapy is considered unsuitable. There are several reasons for this, such as the technical difficulty of the surgery, the controversial nature of hypotensive anesthesia, and concerns about disseminating tumor cells during the operation. Over the past 2 decades, there has been great progress in ocular microsurgery and systemic anesthesia. Furthermore, advances in the molecular biology and cytogenetics of uveal melanomas have improved our understanding of how these tumors grow and metastasize. For these reasons, there is scope for reassessing the place of eyewall resection. The aims of this chapter are to report the main outcomes of eyewall resection of choroidal melanoma by a single surgeon and to discuss the role of this form of therapy in choroidal melanoma management. Patients were considered for primary eyewall resection if: 1) the tumor was considered unsuitable for ruthenium plaque or proton beam radiotherapy because of thickness exceeding 5.5 to 6 mm, and if 2) the patient was highly motivated to keep the eye. Our contraindications were: 1) tumor diameter exceeding 16 to 17 mm; 2) optic disc involvement; 3) clinical evidence of invasion of large areas of the retina or retinal perforation by tumor; 4) involvement of more than 2.5 clock hours of ciliary body, iris, or angle; and 5) poor general health, preventing systemic hypotensive anesthesia. A few patients underwent eyewall resection after plaque or proton beam radiotherapy if the response to the radiotherapy was uncertain or because of extensive exudative retinal detachment threatening the eye. At the end of their initial assessment, patients were informed of all the therapeutic options available, together with the logistics of each type of treatment, the chances of achieving key objectives, and the risks involved in terms of ocular and systemic complications. Eyewall resection was undertaken only if the patient clearly understood the risks of profound systemic hypotensive anesthesia and accepted the evidence-based estimates of developing local tumor recurrence, retinal detachment, and visual loss. The patient was also required to give consent for the eye to be enucleated during the local resection procedure if complications arose. Since 1991, an audiocassette tape recording of the actual discussion was given to all new patients to help them remember what was said. Our technique of transscleral local resection has been described previously.6 Briefly, a conjunctival peritomy was made, extraocular muscles in the operative field were disinserted, and traction sutures were placed in the sclera. The tumor margins were localized by transpupillary transillumination and marked on the sclera with a pen. A polyhedral, lamellar scleral flap was created, hinged posteriorly. Any vortex veins in the operative field were cauterized outside the eye and within sclera. The eye was decompressed by limited vitrectomy, performed with a standard vitrector, using illumination from the operating microscope, and no infusion. Deep scleral incisions were made around the tumor margins to create a stepped wound edge, facilitating closure.