Histological grading of malignancy in squamous cell carcinoma of the oral tongue.

A system for histological grading of malignancy was applied to ninety-five squamous cell carcinomas from the anterior 2/3 of the tongue. Three parameters relating to the tumour cell population and three parameters relating to the tumour-host relationship were evaluated. The expected 5-year survival expressed as % survivors was 88% for patients with tumours having total malignancy scores of less than 13 points. 65% for 13-16 and 44% for patients with tumours having scores of more than 16. The prognostic significance for 5-year survival was statistically valid for the three different groups of malignancy scoring. The conventional classification according to mode of differentiation did not give equally good correlations for survival or occurrence of metastases. For the evaluation of the biological behaviour of lingual carcinomas, histological grading of malignancy is a better method.