31‐GEP (DecisionDx): a review of clinical utility and performance in a Mayo Clinic cohort

Abstract

BackgroundCutaneous melanoma (CM) is a significant health concern because of its high metastatic potential. Gene Expression Profile (GEP) testing, particularly the 31‐GEP test (DecisionDx‐Melanoma), has been increasingly used for risk stratification in CM patients. This study aimed to evaluate the clinical utility and performance of the 31‐GEP test in a real‐world setting.MethodsPatients with CM who underwent 31‐GEP testing from August 2014 to August 2022 at our institution were identified through searches of electronic health records. The study analyzed the influence of 31‐GEP testing on clinical decision‐making related to sentinel lymph node biopsy (SLNB), medical oncology referral, and postdiagnosis surveillance. Kaplan–Meier curves and Cox proportional hazard models were used to elucidate the test's performance, focusing on relapse‐free survival (RFS) and melanoma‐specific survival (MSS).ResultsThe study included 65 CM patients. Dermatologists ordered more than 80% of 31‐GEP tests. In 81.5% of cases, 31‐GEP results did not alter standard clinical management. SLNB decisions were unaffected in 92% of patients with pre‐SLNB 31‐GEP results. Among patients with stage I‐IIA melanoma, 25% of those with high‐risk 31‐GEP results were referred to medical oncology. Contrary to expectations, the rate of nodal metastasis was higher in low‐risk than in high‐risk 31‐GEP cases. Survival analysis showed overlapping RFS and MSS curves between different 31‐GEP classes, suggesting limited prognostic value.ConclusionsThe 31‐GEP test has a limited impact on clinical management decisions and shows limited prognostic value.