ARE RISK FACTORS FOR GROWTH OF CHOROIDAL NEVI ASSOCIATED WITH MALIGNANT TRANSFORMATION? ASSESSMENT WITH A VALIDATED GENOMIC BIOMARKER (AN AMERICAN OPHTHALMOLOGICAL SOCIETY THESIS)

PURPOSE: To test the hypothesis that widely used clinical risk factors for growth of choroidal nevi are associated with malignant transformation. METHODS: Fine needle biopsy for assignment of gene expression profile (class 1 or class 2) was performed in 207 choroidal melanocytic tumors 60 years and tumor thickness >2.25 mm (Fisher exact test, P=.002 for both). Documented growth was not associated with the class 2 profile (P=.5). The odds ratio of a tumor having the class 2 profile was 2.8 (95% confidence interval, 1.3–5.9) for patient age >60 years old and 3.5 (95% confidence interval, 1.4–8.8) for tumor thickness >2.25 mm. For patients with both risk factors, the “number needed to treat” to identify one patient with a class 2 tumor was 4.3 (P=.0002). No other clinical feature or combination of features was associated with the class 2 profile. CONCLUSIONS: None of the widely used choroidal nevus risk factors for tumor growth, nor documented growth itself, is pathognomonic of malignant transformation as defined by class 2 gene expression profile. Patient age and tumor thickness may be helpful for identifying small choroidal melanocytic tumors that are more likely to have the class 2 profile. Observation for growth prior to treatment continues to be reasonable for most patients with suspicious choroidal nevi.