Histopathological grading systems and their relationship with clinical parameters in lower lip squamous cell carcinoma

The objective of this study was to evaluate the histopathological grade of malignancy in a series of lower lip squamous cell carcinomas (LLSCCs) using three histopathological grading systems (invasive front grading system, World Health Organization (WHO) grading system, and histological risk assessment), and to correlate this with clinical parameters (tumour size/extent, regional lymph node metastasis, and clinical stage). Haematoxylin-eosin-stained histological sections obtained from 59 cases of LLSCC were analyzed by light microscopy. Grading of the invasive tumour front showed a significant association between low grade of malignancy and the absence of regional lymph node metastasis (P = 0.030) and initial clinical stage (P = 0.043). No significant associations were observed between the clinical parameters analyzed and the WHO system (P > 0.05). Using the risk assessment, a highly significant association was observed between the risk score and regional lymph node metastasis (P = 0.004) and clinical stage (P = 0.002). In addition, the lymphocytic infiltrate was significantly associated with regional lymph node metastasis (P = 0.017) and clinical stage (P = 0.040). The results of the present study suggest that, among the histopathological grading systems evaluated, the histological risk assessment is the best option to predict the biological behaviour of LLSCCs.