Malignancy grading of the deep invasive margins of oral squamous cell carcinomas has high prognostic value

Several recent studies have indicated that cells at the invasive tumour margins often are different from cells within other parts of various human cancers. In this work, we have studied all squamous cell carcinomas of the floor of the mouth registered in Norway during the years 1963–1972 (N = 96). Borderline cases and cases given no treatment were excluded. Of the remaining 79 cases, biopsy specimens acceptable for histological grading were obtained from 61 patients. Only the most invasive margins of the tumours were histologically graded independently by two pathologists according to a multifactorial grading system. The results confirmed our previous findings that grading of invasive tumour margins is an independent prognostic factor in Cox's multivariate survival analysis (P