Interaction between peritumoral reactivity and histomorphological pattern of lymph node reactivity in oral squamous cell carcinoma: A host immune status indicator.

Abstract

The invasive tumor front (ITF) of oral squamous cell carcinoma (OSCC) and the reactive changes in regional lymph nodes (RLNs) are believed to carry integral prognostic information about the tumor's invasive capacity and insight into host immune response, respectively. This study aims to evaluate the reactivity patterns of RLNs in relation to the tumor stage, grade and various histopathological parameters at the ITF of primary tumor, in an attempt to elucidate the nature of host-immune response to tumor. Pattern of invasion (POI) using Bryne's criteria, peritumoral inflammation, and status of connective tissue (CT) stroma of 50 OSCC cases, that underwent selective neck dissection were assessed at the ITF. Immunoreactivity patterns in corresponding 450 RLNs were assessed as proposed by Tsakraklides and Ioachim. Further, 97 metastatic lymph nodes (LNs) were evaluated for degree and pattern of tumor invasion. The datasets were subjected to the Chi-square analysis. There was statistically significant association (P = 0.001) of Type III and Type IV POI as well as mild peritumoral inflammation (P = 0.024) with the advanced stages of OSCC as compared to early stages. Significant association was observed between LN reactivity pattern and tumor stage (P = 0.05), with metastatic nodes exhibiting germinal center predominance (97.9%) and lymphocyte predominance (69.1%) largely observed in nonmetastatic nodes. Majority of metastatic nodes showed Grade 3 invasion (54.7%) in the form of large islands (57.7%), whereas two (2.1%) nodes were totally effaced by tumor metastasis. Statistical significance was observed between CT stroma at ITF and degree of tumor invasion in metastatic LN (P = 0.001). POI also showed significant correlation with peritumoral inflammation (P = 0.002), CT stroma (P = 0.02), and LN reactivity pattern (P = 0.03). This study supports the presence of a strong immunological host-tumor relationship.