1149P Validation of a model combining clinicopathologic risk factors and a gene expression profile to identify primary melanoma patients who can safely forgo sentinel lymph node biopsy

The sentinel lymph node biopsy (SLNB) procedure has gained importance now that primary cutaneous melanoma (PCM) patients with a positive sentinel lymph node are considered candidates for adjuvant systemic therapy. However, SLNB is an invasive procedure, and approximately 80% of patients lack nodal metastasis. Many SLNB negative patients are exposed to invasive surgery but enjoy no discernible therapeutic benefit. Therefore, there is a need for a non-invasive test to accurately identify PCM patients who may forgo the SLNB procedure due to low risk of nodal metastasis. Previously, a clinicopathological and gene expression profile model (CP-GEP model) has been developed to identify PCM patients who can safely forgo SLNB. Moreover, a validation of the CP-GEP model in a European cohort has been reported. Here, we describe the validation of the CP-GEP model in a US cohort.