Background and Aims: This study was undertaken to identify the comorbidities which have an independent impact on overall survival (OS) and validate the use of Charlson’s comorbidity index (CCI) in patients with oral cavity cancer.

Methods: Data of 472 patients (age, sex, tumor site, Tumor (T) stage, Node(N) stage, comorbidities, and treatment) were collected from the case files and CCI score was calculated. Univariate analysis was done and significant variables were subjected to multiple cox regression analysis to identify the possible independent predictive factors of mortality. Cox proportional hazard model to estimate the hazard ratio for overall survival was used. The survival probability was estimated using Kaplan-Meier method and differences of survival were compared by log rank test.

Results: A univariate analysis done on the variables affecting mortality showed a p < 0.2 for tumor size, nodal spread, hypertension, diabetes, carcinomabuccal mucosa and lower alveolus, age >70 years and CCI score. Nodal spread, hypertension and diabetes mellitus and CCI score were identified as independent predictive factors for overall survival using multiple cox regression. CCI score was identified as an independent predictor of OS using Kaplan Meier analysis. Hypertension (35.2%) was the most common comorbidity in our study population.

Conclusion: Comorbidities have a significant impact on the overall survival of oral cavity cancer patients.CCI score is a valid tool to help the clinician assess the prognosis at initially and enable him to choose the optimal treatment which is less toxic to the patient and more cost effective.

Keywords: Regression Analysis, Comorbidity, Prognosis, Hypertension, Diabetes Mellitus, Head and Neck Neoplasms.

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Dr Mary Thomas

Additional Professor Department of Anesthesiology, Regional Cancer Centre, Trivandrum, Kerala India