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Tracking growth in high-risk choroidal nevi revealed key genetic shifts and low metastatic risk, supporting timely intervention to prevent progression to aggressive UM.
A study published in July 2025 issue of American Journal of Ophthalmology explored genetic differences between melanocytic lesions that were initially observed (IO) and those immediately treated (IT), addressing the gap in large-scale data on small, high-risk choroidal nevi.
Researchers compared genetics and metastatic rates between high-risk nevi IO and treated upon growth vs IT uveal melanoma (UM), and to evaluate whether the growth rate prompting treatment in the observed group was sufficient to maintain low metastatic risk.
They included 272 individuals with UM treated between 2013 and 2022 at a major ocular oncology center in Houston, Texas, all with at least 18 months of follow-up. Individuals were classified into 2 groups: IO and IT. The IO group comprised those diagnosed with high-risk choroidal nevi and monitored until clinical features indicated UM, while the IT group consisted of those diagnosed with UM at their initial visit. The metastatic outcomes, tumor gene expression profile (GEP), tumor preferentially expressed antigen in melanoma (PRAME) status, and tumor growth rates in height and largest base diameter (LBD) [millimeters (mm)/year] were analyzed. Presence or absence of metastasis (yes or no) was also recorded.
The results showed that 213 individuals were in the IT group and 59 in the IO group. The IT group had a significantly higher rate of metastasis (P=0.009), a greater proportion of GEP Class 2 tumors (P=0.010), and increased PRAME expression (P=0.044) compared to the IO group. In the IO group, mean tumor growth rates rose to 0.65 mm/year in height and 1.00 mm/year in the LBD just before treatment (P<0.01).
Investigators concluded that genetic changes and metastatic risk progressed with tumor growth, and tracking the growth rate in high-risk nevi provided a reliable noninvasive marker for identifying transformation to UM without a high incidence of Class 2 tumors or metastasis.