Lymph-Node Ratio in Patients with Cutaneous Melanoma: A Multi-Institution Prognostic Study

Area of Science:

• Oncology
• Dermatology
• Surgical Pathology

Background:

• The lymph node ratio (LNR), defined as metastatic lymph nodes (LNs) over total excised LNs, is a prognostic indicator in various cancers.
• Its prognostic relevance in skin melanoma remains debated, necessitating further investigation.

Purpose of the Study:

• To evaluate the prognostic significance of LNR in melanoma patients.
• To propose integrating LNR into the current American Joint Committee on Cancer (AJCC) N staging system for melanoma.

Main Methods:

• A retrospective analysis of 2,526 melanoma patients with lymph node metastasis from nine Italian institutions.
• Multivariable survival analysis was used to assess the prognostic value of LNR, categorized as A (≤0.1), B (0.11-0.25), and C (>0.25).

Main Results:

• LNR demonstrated significant independent prognostic value for melanoma-specific survival.
• Specifically, LNR categories B and C were associated with worse survival compared to category A (HR 1.47 and 1.84, respectively).
• LNR was prognostic in AJCC N1a and N2a substages but not in N1b, N2b, or N3 substages.

Conclusions:

• The LNR is a valuable prognostic factor for melanoma patients with one (AJCC N1a) or two to three (AJCC N2a) positive lymph nodes after sentinel lymph node biopsy (SLNB).
• This easily obtainable parameter should be considered alongside the number of positive LNs for improved melanoma staging.