Current Methods for the Diagnosis and Treatment of Choroidal Melanoma
tumors), and trans-scleral aspiration into the tumor’s base. Ocular oncologists are not unanimous about which option is better, or whether a stepwise approach starting with a fine-needle aspiration biopsy (FNAB) is possible. No matter which approach is taken, potential dissemination of tumor cells remains a concern.40
Biomarkers for Metastases
The first biomarkers for CM were histopathologic as offered by Callender’s classification, in which predominantly spindle cell melanomas carried the best prognosis, mixed-cell tumors were worse, and epithelioid cell tumors the most likely to metastasize.41
Other
features associated with systemic prognosis include intrinsic tumor vascular patterns, tumor vascular density, tumor size, location of the anterior margin of the tumor, and degree of ciliary body involvement.42,43 It is important to note that in consideration of most of the above, as well as epidemiologic and other clinical factors, the COMS offered the first evidence-based results that patient age and largest tumor dimension were the most significant biomarkers for metastasis by multivariate analysis.16
In 2006, Finger and colleages suggested that
PET/CT imaging specfic uptake value (SUV) could be used as a biomarker for metastatic risk.10 by Lee et al., 2011.44
Metastatic Disease Detection
Although CM is not as aggressive as skin melanoma, Kujala et al. reported mortality rates of 31 % by five years, 45 % by 10 years, 49 % by 25 years, and 52 % by 35 years.45
In this article, we found that the
diagnosis and treatment of metastatic CM varies by country, region, and clinical centers. It is also driven by patient and social and economic factors.
In general, pre-operative metastatic surveys should include a physical examination looking for cutaneous and subcutaneous nodularity as well as hepatomegaly. Radiographic imaging can range from contrast-enhanced abdominal MRI, CT or ultrasound imaging to total body PET/CT.
In that over 90 % of patients present with hepatic involvement, abdominal imaging should be integral to pre-operative staging and subsequent surveillance. However, in a recent study using whole-body PET/CT, 75 % of patients with metastatic CM were noted to have extrahepatic – primarily bone (50 %), lung (25 %), lymph node (25 %), and skin (25 %) – metastases (see Figure 3). This distribution suggests that liver function tests alone are inadequate.24,46,47
There are centers that do not perform metastatic surveys due to a lack of definitive treatment for metastatic CM. At The New York Eye Cancer Center, we currently perform pre-operative surveys to find the <4 % that have detectable disease at presentation.12
Such discovery can eliminate
the need for surgery for the primary CM, reveals synchronous non-ocular tumors, and allows for both systemic staging and early intervention. Follow-up metastatic surveys allow for both early intervention and end-of-life planning.
Tumor Staging
Clinical practice varies greatly from one center to another. Though the COMS defined CMs as small, medium, and large, the Ophthalmic
US OPHTHALMIC REVIEW
Positron emission tomography (PET) reveals a radioactive glucose (18-FDG) uptake measure of physiologic activity, while computed tomography (CT) reveals its anatomic shape and location. This combined PET/CT image puts form and function on the same diagnostic page.
Oncology Task Force of the AJCC, together with the UICC, has recently produced a universally accepted seventh edition AJCC staging system. This five-year effort involved 45 eye cancer specialists from 11 countries.48
Specifically, Chapter 51, Malignant Melanoma of the Uvea, was the result of a retrospective multinational evaluation of over 8,000 patients. This system is now considered ‘universal’ after being widely accepted as a requirement for publication by over 10 major ophthalmic journals and their associated societies. They recognized that standardized reporting would allow for more accurate comparison of diagnostic and therapeutic techniques, as well as the development of biomarkers for CM.
Diagnosis of Choroidal Melanoma—Summary Findings of OPL, thickness greater than 2 mm and subretinal fluid remain the most important diagnostic characteristics of CM. These characteristics are evaluated by ophthalmoscopy, photography with and without angiography, and ophthalmic ultrasound imaging.
Specialized FAF and OCT imaging offer unique and often helpful information about the presence of OPL and subretinal fluid. Ultrasound is best at uncovering obscure basal extensions, vascularity, shifting exudative fluid, scleral extension, and tumor height. Despite all this technology, small CM and indeterminate lesions are typically considered too small for biopsy and are followed for evidence of growth prior to intervention. In summary, clinical, photographic, and ultrasound imaging techniques are currently employed for initial assessment, evaluation of post-treatment regression, and side effects.
65 This observation was recently confirmed
Figure 3: Metastatic Choroidal Melanoma (Arrows) as Seen on Positron Emission Tomography/Computed Tomography
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