Squamous cell carcinoma of the oral cavity. A review of 176 cases with application of malignancy grading and DNA measurements.

This retrospective study comprised 176 patients with squamous cell carcinoma of the oral cavity treated at The Linköping University Hospital over a 19-year period. Clinical parameters, microscopic malignancy grading (according to Jakobsson et al. and Glanz and Eichhorn), DNA cytofluorometry, analysis of therapeutic modalities and statistics regarding survival and prognosis are reported. The mean age was 70 years with a male: female ratio of 1.3:1 One hundred and four patients had T1 or T2 tumours and 109 an N0 neck. Cervical lymph node metastases were more frequent in patients with larger tumours (T3 + T4) than in those with smaller (T1 + T2) (P less than 0.01), in tumours with a high malignancy grading compared to those with a low (P less than 0.05) and in DNA non-diploid tumours compared to diploid ones (P less than 0.001). The aneuploid tumours responded better to preoperative radiotherapy than did diploid (P less than 0.01) or polyploid (P less than 0.05) tumours. Eighty-nine per cent of the recurrences occurred within 1 year of initial therapy. Secondary treatment was successful in 15 of 37 (41%) patients in whom the tumour recurred either at the primary site or in regional lymph nodes, but only in 1 of 8 (12%) with recurrences in both locations. Surgery alone or combined with radiotherapy resulted in equivalent survival rates for tumours in stages I and II. In advanced stages combined radiotherapy and surgery gave better survival figures than either modality alone (P less than 0.01; Kaplan-Meier). The presence of lymph node metastases (P less than 0.001), tumour size (P less than 0.01) and tumour ploidy (P less than 0.005) were the only clinical and histological parameters that significantly influenced survival (Cox regression analysis). Twenty-four patients developed a secondary primary malignancy; 21 of these were located in the aerodigestive tract.