Current Methods for the Diagnosis and Treatment of Choroidal Melanoma
disseminated metastases) found that pre-enucleation EBRT (2 Gy x five daily fractions) did not improve post-enucleation survival.21
Though the
COMS had a significant impact on practice patterns, much has changed over subsequent years. Current practice patterns are based on the characteristics of the CM, visual acuity, treatment modalities available and the patients’ motivation to keep their eye, as well as regional, political, and socioeconomic factors.
The Diagnosis of Choroidal Melanoma Detection
In these cases, CM is an accidental finding during a routine periodic ophthalmic examination. In all other cases, patients present with symptoms of visual loss, metamorphopsia, flashing lights, or floaters. Less common findings have been related to secondary effects, such as cataract, narrow-angle glaucoma, or vitreous hemorrhage. It is not uncommon for a CM to be missed at initial examination, particularly with small ciliary body tumors. The rates of failure to diagnose have been reported within a range of 25–37 %.2,22
In the UK, 45 % of CM patients were reported to be asymptomatic at diagnosis.22
Eye cancer specialists should inquire
about a past medical history of primary lung, breast, or other cancers, systemic diseases, or anticoagulant therapy. These answers may help differentiate CM from simulating lesions.
Anterior Segment Examination
CMs can affect the anterior segment. Common findings include ‘sentinel’ episcleral blood vessels. Less commonly, the tumor can push on the natural lens, inducing a sector cataract (with irregular astigmatism) or angle narrowing. Secondary glaucoma can be seen as irisneovascularization, outflow invasion, or angle closure.23
CMs with massive orbital extension can
be associated with proptosis, papilledema, and exposure keratopathy. These cases may also exhibit an afferent pupillary and/or color vision deficit, as well as ocular motor disturbances.
Ophthalmoscopy
Most CMs can be diagnosed by ophthalmoscopy (see Figure 1). Direct, indirect, and contact lens techniques are employed. Visualization of a pigmented choroidal tumor with the orange pigment lipofuscin (OPL) on the tumor’s surface, significant thickness, and exudative retinal detachment are diagnostic of CM.24
For smaller tumors, photography and ultrasound-assisted documentation of growth may be required.
Over the last 30 years, the misdiagnosis rate for CM has been greatly reduced. For example, the use of experienced examiners, indirect ophthalmoscopy, FA, and ultrasound imaging reduced the COMS misdiagnosis rate to less than 1 %.25,26
Ophthalmic Imaging Techniques
Fundus photography, FAF, and OCT have significantly contributed to the diagnosis and understanding of CM and its associated comorbidities.
Fundus photography plays a unique, central, and indispensable role in the diagnosis and follow-up of CM. Photography should be used to document the initial tumor size, to measure its basal dimensions, and to document its surface characteristics. Furthermore, the distances from the posterior tumor edge to the fovea and optic disk should be recorded. These measurements can be used to help the clinician determine radiation dose
US OPHTHALMIC REVIEW
Beyond diagnosis, post-treatment surveillance of tumor circulation can help determine response to radiation, adjuvant laser therapies, and the onset of secondary vasculopathy (e.g. radiation maculopathy and optic neuropathy).
Ultrasound Imaging
Ultrasound imaging has come to play an essential role in the diagnosis, treatment, and follow-up of patients with CM. Pioneered by Karl Ossoinig and Sandra Frazier Byrne, standardized ophthalmic ultrasound techniques
63
A: Note the pigmented, subfoveal, and juxtapapillary choroidal melanoma with overlying orange pigment lipofuscin (OPL); B: Fundus autofluorescent imaging (FAF) picture of the same tumor demonstrates hyperautofluorescence of the OPL (arrow heads) and dependent alterations of the retinal pigment epithelium due to a serous retinal detachment.
to critical structures and risks for vision loss. Photographic evidence of tumor-associated exudative subretinal fluid, choroidal neovascularization, OPL deposition, and retinal pigment epithelial metaplasia at first offers diagnostic significance and post-treatment measures of tumor response. For example, after treatment exudative fluid and OPL typically regress and the tumor darkens. Photographic documentation of these changes allows the eye cancer specialists to establish the pattern of CM regression. Late radiation changes (including radiation retinopathy and optic neuropathy) can be initially documented and comparatively evaluated for progression or regression by fundus photography.27
FAF has emerged as a powerful tool to document and discover occult OPL. Exudative retinal detachments can also be seen with FAF, particularly when there is an associated acute or chronic retinal pigment epithelial degeneration.3,28
OPL can also be seen as deposits on the retinal pigment epithelium. Some studies suggest that choroidal nevi and their overlying intact retinal pigment epithelium are less likely to allow transmission of light into the tumor’s stroma and subjacent choroid.
Intraocular Angiography
FA and ICG are used to evaluate CM. Angiographic imaging can reveal unique patterns of tumor circulation. For example, a ‘double circulation’ with well-defined blood vessels is rarely seen in metastatic tumors and a ‘coarse vascular pattern’ is characteristic of choroidal hemangioma. Metastatic choroidal tumors typically have poor circulation, characterized by slow uptake, leakage, and stromal dot-like microaneurysms. In select cases, FA or ICG may be the best methods to determine largest basal tumor dimensions prior to the choice of plaque size.
OCT is the most sensitive method of detecting subretinal fluid and intraretinal edema.29
Figure 1: Subfoveal Choroidal Melanoma AB
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