Outcome of oral tongue squamous cell carcinoma in patients with and without known risk factors

Background: Tobacco smoking and high alcohol consumption are considered major risk factors of oral tongue squamous cell carcinoma. This study compared disease outcome between patients with and without known risk factors. Methods: Patients with oral tongue squamous cell carcinoma treated at two major medical centers from 1994 to 2008 were identified by cancer registry search. The medical files were reviewed for background-and-disease-related data, risk factors, and outcome. Results: The study sample consisted of 291 patients: 175 had a history of heavy tobacco smoking and alcohol abuse and 116 did not. Comparison of the patients without risk factors between the two centers yielded no differences in background features. Men accounted for 74% of the total patients with risk factors and comprised 77% of the risk-factor group. The risk-factor group was characterized by a significantly higher mean tumor grade (p = 0.0001) and greater tumor depth of invasion (p = 0.022) than the non-risk-factor group. The 5-year local and regional control rates were 85.3% and 74%, respectively, with no significant difference between the groups. The 5-year overall survival rate was 68% in the risk-factor group and 64% in the non-risk-factor group (p = NS). Separate analysis of patients aged <40 years at diagnosis revealed a worse overall (p = 0.015) and disease-free survival (p = 0.038) in those without risk factors. Conclusions: The outcome of oral tongue carcinoma is similar in patients with and without risk factors. The worse prognosis in younger patients (<40 years) without risk factors suggests that the pathogenesis in these cases involves factors other than smoking and alcohol.