Correlation between TNM classification and malignancy histological feature of oral squamous cell carcinoma

Histological staging of deep invasive margin of oral squamous cell carcinoma has a significant influence on survival of patients since the tumor cells are more poorly differentiated in this area and have high prognostic value. AIM: the purpose of the present study is to correlate TNM clinical classification with histopathologic characteristics (degree of keratinization, nuclear pleomorphism, invasion pattern and lymphoplasmocytic infiltrate) and histologic malignancy scores in 38 cases of oral epidermoid carcinoma in the lesion's deepest areas. STUDY FORM: Retrospective clinical study. MATERIAL AND METHOD: This is a retrospective study based on histological review of 38 cases of oral squamous cell carcinoma selected from the medical files of Hospital Dr. Luis Antonio, Natal - Rio Grande do Norte, Brazil. TNM clinical classification data were obtained from the analysis of the medical records. Two pathologists performed histological malignancy staging on routine 3 µm-thick sections of invasive tumor areas stained with hematoxylin and eosin. For statistical analysis, parametric (ANOVA) and non-parametric tests (Tukey; Pearson; Chi(2)) were employed. RESULTS: We found significant correlation between TNM clinical staging and malignancy mean score (p = 0.001) and histopathologic parameters, such as nuclear pleomorphism (p = 0.016) and degree of keratinization (p = 0.025). Furthermore, there were also statistically significant correlations between lymphocytic infiltration (p = 0.016) and nuclear pleomorphism (p = 0.004) with TNM classification when grouped in two series: TNM I/II and III/IV. CONCLUSION: TNM classification, as well as malignancy mean score, had statistically significant correlation with degree of keratinization, nuclear pleomorphism and lymphocytic infiltration. These highly significant results indicated that histologically invasive areas may be primarily responsible for the clinical behavior of the tumor, and this may be important for the therapy of choice for oral squamous cell carcinoma.