The predictive value of histological classification into degrees of differentiation of squamous cell carcinoma of the larynx and hypopharynx compared with the survival of patients.

In the course of running two clinical trials between 1966 and 1985, data became available for 1315 patients, 713 in the first trial and 602 patients in the second trial, which has allowed comparison between histological findings in laryngeal and hypopharyngeal carcinoma, the observed survival and the tumour-free rates for these patients who were followed for up to 10 years. Extensive histopathology reviews have revealed over 98% agreement on tumour cell type between the initial report and that of the reviewer. Highly significant differences have been found for squamous cell carcinoma between the observed survival and the tumour-free rates for patients with well-differentiated and with anaplastic lesions. There was a statistically significant greater proportion of patients with well-differentiated tumours at larynx sites and in stage 1 when compared with patients with anaplastic tumours, but even when this was taken into account, multivariate analyses showed that tumour grading still made an independent significant contribution to the prediction of prognosis. For squamous cell carcinoma only very simple and rapidly assessed histopathological features need to be identified to classify tumours into the two grades employed in this study. The analyses have confirmed the prognostic significance of tumour grading in squamous cell carcinoma in the larynx and hypopharynx.