The Integrated i31-GEP Test Outperforms the MSKCC Nomogram at Predicting SLN Status in Melanoma Patients

Area of Science:

• Oncology
• Genomics
• Surgical Pathology

Background:

• Sentinel lymph node biopsy (SLNB) is a prognostic tool for cutaneous melanoma, but 88% of patients have negative results.
• Some patients with negative SLNB results may still experience disease progression.
• The integrated 31-gene expression profile (i31-GEP) test offers personalized risk prediction for SLN positivity.

Purpose of the Study:

• To compare the accuracy of the i31-GEP test for SLNB guidance against a nomogram using only clinicopathologic factors.
• To evaluate the performance of i31-GEP in identifying patients with a low risk of SLN positivity.

Main Methods:

• Analysis of 465 patients with T1-T2 tumors and known SLN status.
• Comparison of i31-GEP test results with a Memorial Sloan Kettering Cancer Center (MSKCC) nomogram.
• Application of a 5% risk threshold for SLN positivity.

Main Results:

• In patients with <5% predicted risk, SLN positivity was 2.7% for i31-GEP versus 10.0% for MSKCC (p=0.026).
• The i31-GEP maintained a false-negative rate below the 5% threshold across T-categories for patients predicted to have <5% risk.
• The MSKCC nomogram did not consistently maintain a false-negative rate below the 5% threshold.

Conclusions:

• The i31-GEP test, integrating gene expression and clinicopathologic factors, outperforms nomograms based solely on clinicopathologic factors in predicting SLN status.
• Clinical integration of i31-GEP can enhance patient identification for SLNB.
• Improved patient selection via i31-GEP can lead to more effective risk-aligned management strategies for melanoma.