Paucity of tumor-infiltrating lymphocytes is an unfavorable prognosticator and predicts lymph node metastases in cutaneous melanoma patients

Abstract

Background/aim: Tumor infiltrating lymphocytes (TILs) have been a subject of growing scientific interest; however, a full picture of their role in cancer pathogenesis is still unclear. The present study aimed to reveal correlations between TIL grade and clinicopathological features, especially 5-year survival parameters in cutaneous malignant melanoma (CMM) patients.

Materials and methods: Presence of TILs was assessed by hematoxylin and eosin staining in routine diagnostic histopathological specimens from 104 patients with cutaneous melanoma.

Results: In the entire group of 104 patients, decreasing TIL intensity was a highly negative prognostic factor and indicated considerably shorter overall survival (OS), cancer-specific overall survival (CSOS) and disease-free survival (DFS). We also report on a significant association between decreased TIL intensity and worse prognosis in lymph node-negative patients. Shorter survival (p=0.002 for OS, p=0.038 for CSOS and p=0.011 for DFS) was observed in patients with negative sentinel lymph node biopsies (SLNB), as well as in patients with lack of metastases in regional lymph nodes (p=0.034 for OS, p<0.001 for CSOS and DFS).

Conclusion: Our results indicate that TIL grade is a valuable diagnostic parameter that may be helpful in risk stratification in CMM.

Keywords: Tumor-infiltrating lymphocytes; malignant melanoma; prognosis; prognostic marker.