Role of Observation
Iris melanomas have relatively good outcomes with a 5-year survival rate of more than 95%. They are predominantly of the spindle-cell type and are usually smaller in size than posterior melanomas because of earlier detection. Conservative management is generally advocated whenever possible, but surgical intervention may be justified with unequivocal tumor growth or with extensive disease at initial examination.
The management of small choroidal melanomas is controversial, and it is not clear whether treatment of small tumors prevents metastasis. The natural history of small choroidal melanoma is poorly understood. Small, pigmented, choroidal lesions cannot always be differentiated reliably on examination. Growth is a presumed indicator of malignant potential. The likelihood of progression from the time of diagnosis to the time when tumor growth warrants treatment has not been well characterized. Some ophthalmologists advocate observation. This has been justified on several grounds, including the difficulty with establishing a correct diagnosis, the lack of any documented efficacy for globe-conserving treatments, and concerns for severe treatment-related morbidity. Others have advocated earlier therapeutic intervention.[1,3,4]
Although patients diagnosed with small choroidal tumors were not eligible for participation in the Collaborative Ocular Melanoma Study (COMS), these patients were offered participation in a prospective follow-up study to evaluate the natural history of small lesions. Two-year and 5-year tumor growth estimates of 21% and 31%, respectively, were reported. Clinical risk factors associated with tumor growth included:[3,5]
- Increased tumor thickness.
- Presence of subretinal fluid.
- Orange pigmentation.
- Absence of drusen.
- Absence of retinal pigment.
- Margin at the optic disc.
- Epithelial changes surrounding the tumor.
Role of Surgery
The selection of treatment depends on the following:
- Site of origin (choroid, ciliary body, or iris).
- Size and location of the lesion.
- Age of the patient.
- Occurrence of extraocular invasion, recurrence, or metastasis.
In the past, enucleation (eye removal) was the standard treatment for primary choroidal melanoma, and it is still used for large tumors. However, enucleation has been largely replaced by radiation therapy (i.e., brachytherapy with radioactive plaques; or external-beam, charged-particle radiation therapy) to spare the affected eye.[6,7]