Abstract
Background/Objective: To compare genetic profiles and metastatic outcomes of patients with initially observed indeterminate choroidal lesions (IL), to patients with small choroidal melanomas treated immediately. Methods: In this retrospective comparative cohort study, gene expression profiling (GEP) data of patients initially diagnosed with indeterminate choroidal lesions (IL) and treated with radiotherapy upon documented growth was compared to a control cohort of patients immediately treated for T1a choroidal melanoma (IT). Results: In the IL group 18 patients, and in the IT group 41 patients, were included. Groups were similar in age and tumor thickness at treatment (median 2.4mm IL vs 2.5mm IT, p = 0.34). The IL group had greater largest basal diameter (p = 0.02). No statistically significant difference was found in distribution of GEP, PRAME status, or presence and type of driver mutations. The proportion of class 2 tumors was 33% in the IL group vs. 24% in the IT group (p = 0.64). No difference in metastasis or mortality was observed (p = 1.0 and p = 0.66, respectively). Conclusion: Among comparable cohorts of transformed indeterminate lesions and small choroidal melanomas, no differences in genetic profiles and metastatic outcomes were identified. However, the proportion of class 2 tumors in early-stage melanoma remains substantial. These findings suggest that an observation period for indeterminate lesions does not appear to influence genetic profile or metastatic risk.