Oral squamous cell carcinoma (OSCC) is one of the most common cancers in geographic regions where betel quid (BQ) chewing is prevalent; OSCC is an extremely malignant neoplasm whose prognostic factors are multiple and complex. The purpose of this study was to assess clinicopathological prognostic factors and treatment outcomes in 698 consecutive OSCC patients who had undergone surgery as the primary treatment in an area with a high prevalence of both betel quid chewing and tobacco smoking. The prognostic factors were predicted using Cox's proportional-hazards regression model, and the survival rate was calculated using Kaplan-Meier analysis. The median followup for all patients was 44 months. The 5-year cumulative overall, disease-specific, and locoregional control survival rates were 61%, 62%, and 46%, respectively. Multivariate analysis showed that the lower level of nodal metastasis, advanced stage, tumor thickness >7 mm, and treatment failures were independent risk factors of overall survival. Furthermore, history of alcohol drinking, lower level of nodal metastasis, advanced stage, poor cell differentiation, and treatment failures were independent predictors of poor disease-specific survival. However, we did not find any significant factor that affected locoregional recurrence. Due to the high frequencies of locoregional recurrence and second primary cancer, our findings emphasize that aggressive surgical excision, adjuvant treatments according to clinicopathological prognostic factors and close surveillance are important to the survival of OSCC patients in an area with a high prevalence of betel quid chewing and tobacco smoking.
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