Survival and Factors Associated with Mortality among Patients with Oral Cancer at a Tertiary Hospital in Northeastern Thailand: A Retrospective Cohort Study

Background: Oral cancer is a major cause of premature mortality in Thailand. This study examines survival and prognostic factors in a northeastern tertiary-care setting. Methods: A hospital-based retrospective cohort study was conducted using the Cancer Registry and medical records in a tertiary care hospital in Northeastern, Thailand. Patients diagnosed with oral cancer between January 2005 and December 2015 and followed until death or February 2020. Overall survival was estimated using the Kaplan–Meier method. Cox proportional hazards models were used to assess factors associated with mortality Results: The median survival time was 18.67 months (95% confidence interval CI: 15.70–22.83). It revealed that older age (51–69: adjusted Hazard Ratio AHR = 1.34, 95%CI: 1.06-1.69; ≥70: AHR = 1.85, 95%CI: 1.42-2.41), advanced stage (III–IV: AHR = 1.99, 95%CI: 1.47-2.69) or unknown stage (AHR = 1.53, 95%CI: 1.04-2.26), distant metastases (AHR = 1.64, 95%CI: 1.21-2.22), several primary tumor sites (e.g., tongue AHR = 1.82, 95%CI: 1.30-2.55; oropharynx AHR = 1.89, 95%CI: 1.26-2.84), and surgery (AHR = 1.88, 95%CI: 1.49-2.39) were associated with mortality. In contrast, subjects who were female sex (AHR = 0.77, 95%CI: 0.64-0.94) and had supplement therapy (AHR = 0.71, 95%CI: 0.57-0.87) were associated with lower mortality. Conclusion: Survival among oral cancer patients in this tertiary hospital was poor. Older age and advanced disease at diagnosis were key drivers of mortality, highlighting the need for earlier detection, complete staging, and strengthened supportive care. Keywords: Oral cancer, Survival analysis, Advanced stage, Distant metastases, Age, Sex differences, Thailand