The Integrated 31-Gene Expression Profile (i31-GEP) Test for Cutaneous Melanoma Outperforms a Clinicopathologic-only Nomogram at Identifying Patients who can Forego Sentinel Lymph Node Biopsy

Introduction: National guidelines for cutaneous melanoma suggest avoiding sentinel lymph node biopsy (SLNB) if the risk of SLN positivity is <5% (T1a with no high-risk features), considering SLNB 5-10% additional features (T1aHR) and T1b), offering >10% (T2-T4). Because most patients (88%) who undergo an have a negative result, novel tools to identify can safely forgo are critical. The integrated 31-gene expression profile (i31-GEP SLNB) test combines tumor molecular biology clinicopathologic provide precise positivity. Melanoma Institute Australia (MIA) developed nomogram that uses only predict positivity.
 Methods: We compared i31-GEP MIA in T1-T2 tumors complete data (n=582). precision each tool was analyzed using 95% confidence intervals. To be considered low risk, predicted must upper interval ≤10%, high-risk, lower CI ≥5%.
 Results: identified 28.5% (166/582) as having while also ≤10% 0.9% (5/582, p<0.001) nomogram. In pre-test likelihood (T1aHR-T1b), reclassified 60.2% (171/284) being or 13.7% (39/284, known status (n=466), 22.1% (103/466) 3.9% (4/103) rate 0.6% (3/466, by 33.3% (1/3) rate.
 Conclusions: outperformed identifying could forego SLNB. Integrating 31-GEP stratification provides better guide patient management tumors, whom guidance impactful.