Background: Low socioeconomic status, increasing age, and poor lifestyle behaviors are associated with poor survival in patients with oral cavity squamous cell carcinoma (OCSCC). To determine the overall survival (OS) and the risk of OCSCC death by tumor subsite.
Material and methods: A retrospective cohort study of OCSCC patients diagnosed from 2007 to 2009 and treated at a single cancer center in Rio de Janeiro, Brazil. Patient information was obtained from the Hospital Cancer Registry (HCR) database and complemented by individual search of physical and electronic medical records. Descriptive statistics of population characteristics were computed. OS was estimated using the Kaplan-Meier method. Univariate and multivariate Cox proportional hazards regression analyses were used to estimate the risk of death by tumor subsite.
Results: Seven hundred and three patients with OCSCC were identified. Most patients were men (77.4%) with low levels of education (67.5%), who drank (73.9%) and smoked (79.7%). The most prevalent tumor site was the tongue (45.4%), 73.4% of patients had advanced (clinical stage III or IV) OCSCC at diagnosis and 74.1% died during follow-up. For the entire cohort, the OS was 39.1% at two years and 27.9% at five years. The median survival time was 1.4 years (95%CI: 1.2‒1.5). Non-operative treatment (HR: 3.11; 95%CI: 2.26‒4.29; p<0.001), advanced stage (HR 2.14; 95%CI 1.68-2.74; p<0.001), and age >60 years at diagnosis (HR: 1.37; 95%CI: 1.15‒1.64; p<0.001) were independently associated with the risk of death. However, these factors varied by tumour subsite.
Conclusion: Analysis of specific subsites of the oral cavity revealed substantial differences in prognostic factors associated with poor survival in OCSCC.