Predictive factors for distant metastasis from oral and oropharyngeal squamous cell carcinoma

The presence of distant metastasis after the initial treatment of head and neck squamous cell carcinoma is not considered a common event and is associated with a poor outcome. The objective of this study was to investigate the prevalence and risk factors associated with the diagnosis of distant metastasis in oral and oropharyngeal carcinoma patients. The medical charts of 2327 patients treated from 1954 to 1997 were reviewed. They were 1703 patients (73.2%) with oral cavity and 624 (26.8%), oropharyngeal tumours. Regarding the primary treatment: 637 patients (27.4%) underwent surgery alone; 1147 (49.3%), radiotherapy alone and 543 (23.3%), combined treatment (surgery and radiotherapy). During the follow-up period after the initial treatment, 89 patients (3.8%) were diagnosed with distant metastasis. The variables associated with the distant metastasis-free survival were: tumour site (p=0.008); T stage (p<0.001); N stage (p<0.001); treatment performed (p<0.001) and decade of admission at the institution (p<0.001). The multivariate analysis (Cox regression) showed that the clinical stage (p=0.007); treatment performed (p=0.012) and decade of admission at the institution (p=0.004) were independent predictive factors for distant metastasis. Distant metastasis has been diagnosed more frequently in the latter decade and the significant predictors associated with its presence were the advanced clinical stage and patients who had undergone combined treatment.