Tagging the pre-metastatic node in oral cancer: A cross-sectional study.

INTRODUCTION: Lymph node involvement is the first indication of spread of oral squamous cell carcinoma (OSCC) and it is also a most significant prognostic factor. Lymph nodes show various tumor-induced histological changes preceding actual metastasis, viz. increased vascularity, follicular hyperplasia and desmoplasia which leads to pre-metastatic niche formation. This pre-metastatic niche primarily provides a favorable microenvironment to for the survival and subsequent growth of cancer cells within the lymph node. AIM: A retrospective study to evaluate carcinoma-induced changes in lymph nodes harvested from radical neck dissection in OSCC patients. OBJECTIVES: 1) To evaluate cancer-induced histological changes in positive and negative lymph nodes in OSCC patients. 2) To look for common histopathological changes in both pre-metastatic and metastatic lymph nodes. MATERIALS AND METHODS: Forty lymph nodes harvested from seven OSCC patients were sectioned and stained (Hematoxylin-Eosin) for documentation of histologically evident morphological and functional alterations. The Chi-square test was applied between the non-metastatic and metastatic lymph nodes findings and a statistically significant difference was seen. RESULTS: Sections from 28 negative nodes showed changes associated with pre-metastatic niche conditioning whereas, 12 sections exhibit frank metastases. CONCLUSION: The modified immunological responses and remodeling of the vasculature are the most common histologic tumor-induced pre-metastatic changes. This study reviewed and categorized these histological changes that point to pre-metastatic niche conditioning of lymph nodes.