Histologic grading of the tumor/tissue interface to predict lymph node metastasis in squamous cell carcinoma of the tongue.

BACKGROUND: The invasive front is presumed to contain the most aggressive subpopulation of tumor cells that ultimately invade, spread locally and metastasize. Studying the histopathological grading of the tumor/ tissue interface at the invasive front may help in developing the treatment plan. OBJECTIVES: The aim of this study was to check the reliability of the tumor/tissue interface in predicting lymph node metastasis in oral squamous cell carcinoma (OSCC) of the tongue by evaluating the following: the histopathological grading of hematoxylin and eosin (H&E)-stained excision biopsy specimens according to the modified version of Broder's classification system; and the invasive tumor front (ITF) with the modified version of Bryne's grading system. The study also aimed at studying the lymph nodes for metastases and comparing these histopathological grading systems and lymph node metastases. MATERIAL AND METHODS: All retrospective and prospective cases from the archives of the Department of Oral Pathology and Microbiology of the A.B. Shetty Memorial Institute of Dental Sciences (ABSMIDS), NITTE University in Mangalore, India, collected during the period from 2012 to 2014 were considered for histopathological grading. RESULTS: This study found a significant association between the modified version of Bryne's ITF grading system and lymph node metastases whereas the widely used modified version of Broder's classification failed to show any statistical significance. Only the multifactorial malignancy grading of the deep invasive margins of OSCC proved to be of high prognostic value. CONCLUSIONS: The study found that the degree of keratinization, nuclear polymorphism, the pattern of invasion, and the host response showed significant variation at the invasive front of the tumor as compared to superficial parts, which makes Bryne's grading system more reliable than Broder's grading system.