Gene Expression Profile-Based Test to Predict Melanoma Sentinel Node Status: The MERLIN_001 Study

Area of Science:

• Oncology
• Dermatology
• Genomics
• Surgical Pathology

Background:

• Contemporary guidelines recommend sentinel lymph node biopsy (SLNB) for melanoma patients with >10% risk of SLN metastasis.
• Accurate identification of low-risk patients can refine SLNB selection, avoiding unnecessary procedures.
• A gene expression profile (GEP)-based test offers potential for improved risk stratification.

Purpose of the Study:

• To evaluate the predictive capability of a combined clinicopathological factors and GEP (CP-GEP) test.
• To identify primary cutaneous melanoma patients who can safely forgo SLNB.
• To assess the prognostic value of CP-GEP for outcomes after negative SLNB (not reported herein).

Main Methods:

• A multicenter, prospective, blinded prognostic study involving 1761 patients with T1-T3 cutaneous melanoma.
• CP-GEP testing was performed on primary melanoma tissue to assess SLN metastasis risk.
• Patients were considered candidates for SLNB based on standard clinical criteria.

Main Results:

• The CP-GEP test identified 37.0% of patients as low risk, with a negative predictive value (NPV) of 92.9% for SLN metastasis.
• High-risk cases had a significantly higher SLN-positive rate (23.8%) compared to low-risk cases (7.1%).
• The proportion of low-risk CP-GEP results decreased with increasing tumor stage (T1: 68.2%, T2: 32.9%, T3: 2.8%).

Conclusions:

• The CP-GEP test reliably identifies melanoma patients with a low risk (<10%) of sentinel lymph node metastasis.
• SLN metastasis rates were approximately threefold higher in high-risk versus low-risk CP-GEP cases.
• CP-GEP may enhance shared decision-making between patients and surgeons regarding SLNB.