Distant metastases after definitive radiotherapy for squamous cell carcinoma of the head and neck

Purpose. To analyze parameters that influence the risk of distant metastases after definitive radiotherapy. Methods. Between 1983 and 1997, 873 patients were treated with definitive radiotherapy and had follow-up for 2 years or more. Univariate and multivariate analyses were performed to evaluate risk factors that might influence the risk of distant metastases. Results. The 5-year distant metastasis-free survival rate was 86%. Univariate analyses revealed that the risk of distant metastases was significantly influenced by gender (p =.0092), primary site (p=.0023), T stage (p<.0001), N stage (p<.0001), overall stage (p<.0001), level of nodal metastases in the neck (p<.0001), histologic differentiation (p =.0096), control above the clavicles (p<.0001), and time to locoregional recurrence (p<.0001). Multivariate analysis of freedom from distant metastases revealed that gender (p=.0390), T stage (p<.0001), N stage (p=.0060), nodal level (p<.0001), and locoregional control (p<.0001) significantly influenced this end point. Multivariate analysis revealed that gender (p=.0049), T stage (p<.0001), N stage (p<.0001), and locoregional control (p<.0001) significantly influenced cause-specific survival. Conclusions. The risk of distant metastases after definitive radiotherapy is 14% at 5 years and is significantly influenced by gender, T stage, N stage, nodal level, and locoregional control. (C) 2003 Wiley Periodicals, Inc.