Prospective flow cytometric analysis of head and neck carcinomas. Prognostic relevance of DNA-content and S-fraction.

Flow cytometric data were obtained from 142 primary squamous cell carcinomas of the oral cavity or the oropharynx. Aneuploidy was found in 36.8% of the tumours. The DNA indices showed a significant correlation with the S-fraction, tumour size and evidence of suspicious lymphnodes. There was no clear correspondence between the S-fraction and the tumour stage. Tumour size, histopathologically-positive lymphnodes and the mode of treatment were significantly correlated with the survival rates. In contrast, there was no clear correlation between flow cytometric data and the prognosis of the whole group as well as several clinical subgroups. In 40 patients who received preoperative irradiation, DNA indices and S-fractions were compared before and after the preoperative treatment. In 12 of 14 aneuploid tumours irradiation led to a decrease in the DNA indices into the range of euploidy. Only 2 tumours remained aneuploid. After irradiation 26 of 37 tumours showed a decrease in S-fraction, 11 tumours showed an increase. Loss of aneuploidy after irradiation was associated with a histologically-proven increasing devitalization of tumour cells, decrease in S-fraction corresponded to a tendency to a better prognosis.