Uveal Melanoma
Uveal Melanoma—Where are We Going? Miguel A Materin, MD1
and Bertil Damato, MD, PhD, FRCOphth2
1. Assistant Professor, Director, Ocular Oncology Section, Department of Ophthalmology and Visual Science, Yale University School of Medicine, New Haven; 2. Honorary Professor in Cancer Studies, Consultant Ophthalmologist, Ocular Oncology Service, Royal Liverpool University Hospital
Abstract
Despite good local tumor control, about 50% of patients affected by uveal melanoma die of their disease. Poor prognosis has been related to increased patient age, larger tumor size, ciliary body involvement, epithelioid cell type, extraocular extension, lymphocytic infiltration and high mitotic rate. In recent years, cytogenetic analysis has shown a strong impact on the management of these patients. Since monosomy of chromosome 3 proved to be a high predictive factor for metastatic disease, more ocular oncologists perform tumor biopsy almost routinely. However, there are still controversies regarding these results, such as sampling errors, mainly of disomy 3 results; the impact on quality of life; and the presence of other chromosomal abnormalities that correlate with prognosis as recently described in the literature (e.g. chromosomes 6, 8, 15 and 18). New classification of uveal melanomas as class 1 or class 2 tumors, indicating low and high risk for metastasis, respectively, has also been proposed using gene expression profiles.
Keywords Melanoma, biopsy, cytogenetics, chromosome 3, gene expression, metastasis
Disclosure: The authors have no conflicts of interest to declare. Received: August 8, 2010 Accepted: February 21, 2011 Citation: US Ophthalmic Review, 2011;4(1):105–7 Correspondence: Miguel A Materin, MD, Department of Ophthalmology and Visual Science, Yale School of Medicine, 40 Temple Street, Suite 3A, New Haven, CT, 06510. E:
miguel.materin@
yale.edu
Uveal melanoma is the most common intraocular primary malignancy. The incidence is reported to be four to seven per million per year in the Caucasian population. Patients usually present around the fifth or sixth decade of life; however, this tumor can rarely occur in young children. The large majority of patients are Caucasian, with this malignancy rarely occurring in Hispanics, Asians and African-Americans.1
There is no sex
preponderance. Risk factors for uveal melanoma include fair skin, light-colored eyes, melanocytoma, congenital ocular melanocytosis and neurofibromatosis.
Presentation and Diagnosis
Patients usually present with visual symptoms such as metamorphopsia, blurred vision, photopsia and visual field loss. A significant minority are asymptomatic and detected on routine examination.
Clinical diagnosis is mostly based on indirect ophthalmoscopy combined with ultrasonography and, in selected cases, biopsy.2
Misdiagnosis is
rare in specialist centers. Small melanocytic tumors of uncertain malignancy tend to be observed for tumor growth. Shields et al. have described clinical risk factors for growth and metastasis.3–5
Traditionally, uveal melanoma has been classified as small (less than 3mm in thickness), medium (3–10mm in thickness or up to 15mm in basal diameter), and large (more than 10mm in thickness or more than 15mm in basal diameter).
© TOUCH BRIEFINGS 2011
Ocular Treatment
Treatment is based on tumor size and location, visual acuity, status of the fellow eye, and the patient’s fears and wishes.6
Treatment options
for uveal melanoma include brachytherapy, proton beam therapy, stereotactic radiotherapy, trans-scleral local resection, transretinal endoresection, transpupillary thermotherapy, and enucleation. In most centers, the first choice of treatment is brachytherapy, using either an iodine-125 or ruthenium-106 plaque. Proton beam radiotherapy is available only in a few centers, where it is used either in all patients (e.g. Boston) or in selected cases, when brachytherapy is not appropriate (e.g. Liverpool). There is growing interest in stereotactic radiotherapy in centers where proton beam radiotherapy is not available. Trans-scleral local resection is widely practiced for small iris and ciliary body tumors but performed by only a few surgeons as a treatment for large, choroidal melanomas. Transretinal endoresection is controversial because of concerns that piecemeal tumor removal might disseminate malignant cells around the eye and systemically; it is therefore performed only when it offers the only hope of conserving useful vision. Transpupillary thermotherapy and photodynamic therapy can be successful with small tumors, but are less reliable than radiotherapy and therefore administered only in selected cases (e.g. elderly patients with diabetes mellitus). Increasingly, different therapeutic modalities are being combined to enhance local tumor control while minimizing ocular morbidity. Procedures such as secondary local resection, transpupillary thermotherapy, photodynamic therapy, sector laser photocoagulation,
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