Characterizing the Use of a Commercial 31-Gene Expression Profile Test for Melanoma Risk Stratification at a Large Referral Center from 2015-2023

Summary: Traditional melanoma risk stratification relies on clinicopathologic features to guide prognosis, sentinel lymph node biopsy (SLNB) decisions, and adjuvant therapy.1 • Many early-stage melanomas can still recur/metastasize despite low-risk clinical staging, leading to interest in molecular/genomic testing for more personalized management.2,3 • A commercially available 31-gene expression profile (GEP) test (DecisionDxMelanoma; Castle Biosciences) is purported to predict recurrence/metastasis risk and provide stage-independent stratification:4,5 Class 1A: Low risk Class 1B/2A: Intermediate risk Class 2B: Highest risk • The test has been used in clinical practice to complement traditional staging and guide more aggressive management, especially in thin melanomas.6,7 • This study characterizes usage trends, patient/tumor characteristics, and clinical impact of 31-GEP testing at a large referral center (2015-2023).