Tumor-Infiltrating Lymphocytes in Patients with Melanoma: Which Is Its Prognostic Value?

Area of Science:

• Oncology
• Immunology
• Dermatology

Background:

• The prognostic significance of tumor-infiltrating lymphocytes (TILs) in melanoma is debated.
• Understanding TILs' impact on melanoma progression and patient outcomes is crucial for treatment strategies.

Purpose of the Study:

• To investigate the association between TILs and melanoma-specific survival (MSS).
• To evaluate the correlation of TILs with recurrence-free survival (RFS).
• To determine the relationship between TILs and sentinel lymph node (SLN) status in melanoma patients.

Main Methods:

• Retrospective analysis of 386 melanoma resections from 2009-2019.
• Classification of TILs using the Melanoma Institute Australia grading system into high (G1: grades 1-3) and low (G2: grade 0) groups.
• Analysis of SLN biopsy positivity and survival data (MSS, RFS) with a mean follow-up of 48 months.

Main Results:

• Lower SLN positivity rates were observed with increasing TILs grades (32% for grade 0 vs. 0% for grade 3, p=0.02).
• Patients with higher TILs (G1) demonstrated significantly better 5-year MSS (86% vs. 75%, p=0.002) and RFS (81% vs. 60%, p=0.004) compared to those with grade 0 TILs (G2).

Conclusions:

• Tumor-infiltrating lymphocytes in melanoma are significantly associated with sentinel lymph node status.
• Higher levels of TILs correlate with improved melanoma-specific survival and recurrence-free survival, suggesting a favorable prognostic role.