LB1003 The 31-GEP stratifies risk of recurrence and metastasis in 894 medicare-eligible patients with cutaneous melanoma

Abstract

Background: The incidence of cutaneous melanoma (CM) is rising, particularly among older patients who generally have worse outcomes than younger patients. The 31-gene expression profile (GEP) test stratifies patient risk of recurrence and metastasis into low (Class 1A), intermediate (Class 1B/2A), and high risk (Class 2B). The study goal was to demonstrate the 31-GEP provides critical risk information for Medicare-eligible patients, allowing providers to identify patients who may benefit from increased surveillance or therapeutic treatment. Methods: Retrospective analysis of patients over 65 years old enrolled in previous studies who received 31-GEP testing (n=894). Recurrence-free survival (RFS) and distant metastasis-free survival (DMFS) were assessed using Kaplan-Meier, log-rank test, and Cox regression multivariable analysis. Results: Patients with a Class 1A 31-GEP result had higher 5-year RFS (93.9% vs. 52.0%, p<0.001) and DMFS (96.3% vs. 64.8%, p<0.001) than patients with a Class 2B result. A Class 2B result was a significant predictor for RFS (HR=4.66, p<0.001) and DMFS (5.34, p<0.001) in multivariable analysis including AJCC 8th edition stage. Stage II (RFS: HR=2.37, p<0.001; DMFS: HR=1.83, p=0.033) and stage III disease (RFS: HR=6.22, p<0.001; DMFS: HR=6.20, p<0.001) were also significant. Older patients with a negative SLNB and a Class 1A 31-GEP result had higher 5-year RFS (88.2% vs. 53.0%, p<0.001) and DMFS (93.0% VS. 69.4%, p<0.001) than those with a Class 2B result. Class 1A patients who did not receive a SLNB had high RFS (98.2%) and DMFS (99.1%). Conclusions: The 31-GEP test stratified risk of recurrence and survival in Medicare-eligible patients and added independent prognostic information to current staging methods. In patients with a potentially large number of comorbidities, identifying those who can forego more extensive therapy is vital.