Estimation of Prognosis in Invasive Cutaneous Melanoma: An Independent Study of the Accuracy of a Gene Expression Profile Test

BACKGROUND Cutaneous melanomas (CMs) with similar clinical and histopathologic features can harbor differing capacities for metastasis. A validated gene expression profile (GEP) test offers prognostic information by classifying CMs as low risk (Class 1A/1B) or high risk (Class 2A/2B) for metastasis. OBJECTIVE The authors sought to perform an independent study of the predictive accuracy of the GEP test, to determine what clinical and histopathologic features predict high-risk classification, and to evaluate how intermediate classes (1B & 2A) performed clinically. MATERIALS AND METHODS Using our institution's prospectively collected melanoma registry, the authors identified patients who had been treated for CM within the last 5 years and undergone GEP testing. Clinical, histopathologic, and outcomes data were analyzed. A subcohort of patients with known metastatic disease were identified and tested. RESULTS The GEP test accurately identified 77% of metastatic CMs as high risk (Class 2). The GEP had a negative predictive value of 99% for Class 1 CMs. Class 2 CMs were 22 times more likely to metastasize. CONCLUSION The GEP test's performance in our independent cohort corresponded with previous industry-sponsored studies and proved to be a helpful clinical prognostic tool with the potential to direct patient care protocols.

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