Primary radiotherapy of carcinoma of the supraglottic larynx - A multivariate analysis of prognostic factors

Purpose: The aim of this study was to analyze the importance of different possible prognostic factors in cancer of the supraglottic larynx. Methods and Materials: Nine hundred thirty-two patients with carcinoma of the supraglottic larynx were consecutively treated at The Finseninstitute in Copenhagen between 1966 and 1991. Of the patients, 768 treated with radiotherapy only were eligible for a multivariate Cox regression analysis of prognostic factors with local-regional control as endpoint. Of these, 73% (561) were men and 27% (207) women. Twelve factors: Age; gender; tumor size; site; T category (UICC78); nodal involvement (UICC 78); stage (UICC78); treatment period; tumor surface appearance; histopathologic differentiation; cord mobility; and hemoglobin level were tested. Results: Only gender, T, N, and size proved to have independent significant prognostic importance in the multivariate analysis. A hazard index including these four factors for each patient was calculated, and eight risk groups formed. When the relative risks (RR) for these groups were plotted against the corresponding 5-year local-regional control failure rates, a very simple equation for the risk of failure could be derived as: 5-year local failure risk=0.2+0.1 RR. Conclusion: We recommend that this estimation of an individual patient's risk of failure should be implemented in future clinical decision making