Comparative Metastatic Rates in GEP Class 1A versus 1B Posterior Uveal Melanoma: Results Contrary to Expectations.

Purpose: The purpose of this study was to determine whether the metastatic rates in patients with gene expression profile (GEP) class 1A versus 1B posterior uveal malignant melanoma supported or contradicted predictions of very low metastatic rate in GEP 1A cases and moderate rate in GEP 1B cases.

Patients/methods: 164 patients with a cytopathologically confirmed primary posterior uveal malignant melanoma classified by GEP testing as class 1 (100 GEP 1A, 64 GEP 1B) were evaluated. Kaplan-Meier rates of metastasis were computed and plotted for the GEP class 1 subgroups. Median follow-up of patients who were still alive without metastasis on the date of data analysis was 100.5 months for the GEP 1A patients and 97.2 months for the GEP 1B patients.

Results: The actuarial 5-year rate of uveal melanoma metastasis was 10.8% (std. error = 3.2%) in the GEP 1A patients versus 0% in the GEP 1B patients, and the actuarial 10-year rate of metastasis was 12.2% (std. error = 3.5%) in the GEP 1A patients versus 2.1% (std. error 2.1%) in the GEP 1B patients.

Conclusion: The results of this retrospective single-center study cast doubt on the validity of the prognostic stratification of GEP class 1 posterior uveal malignant melanomas into very low risk (GEP 1A) versus intermediate risk (GEP 1B) of metastasis subgroups provided by the commercially available GEP test.