Data from a clinical trial involving 734 patients have shown the value and the deficiencies of the current Union Internationale Contre le Cancer's tumor, node, and metastasis classification system for prognostic purposes. The tumor-category classification provides a good discriminant for both nodal involvement and survival; however, the previous node classification system only discriminated between node-negative and node-positive patients, as nodal fixity was not found to be a discriminator. The current anatomical site classification is ambiguous for some laryngeal and pharyngeal subsites, and modifications to the present system based on prognostic values are proposed. A difference in patient age between tumor categories has been shown, and various differences in incidence and survival data for the sexes have been demonstrated. Differences in observed and expected survival rates are related to continued late deaths from tumor. Multivariate analyses have shown that stage grouping is the most powerful prognostic discriminator, followed by anatomical site and age.