Significant Prognostic Factors Influencing the Survival Difference of Oral Tongue Squamous Cell Carcinoma.

Background: Oral tongue squamous cell carcinoma is the most common malignancy in the oral cavity. Overall survival varies across many countries, and poor prognosis is prevalent in developing countries, including Thailand. Our study aimed to identify prognostic factors that affected survival for oral tongue cancer in Thailand.

Methods: We performed a retrospective study of 183 patients diagnosed with oral tongue squamous cell carcinoma between January 2012 and December 2016 and who underwent multidisciplinary treatment. The disease stage was classified by tumor-nodes-metastasis (TNM) staging system. The survival outcome was calculated and represented in median survival time. Univariate and multivariate Cox proportional hazards models were used to identify factors that impacted survival outcomes.

Results: A clear margin was achieved in 88.8% of the 125 operated patients. Radiotherapy was given to 115 patients (62.84%). The survival shown in Kaplan-Meier curves was significantly lower according to advanced TNM stage, poor histologic grade, nonsurgical treatment, and patients treated with radical neck dissection. Radiotherapy was a good prognostic factor [hazard ratio (HR) 0.25, = 0.022]. Poor prognostic factors were body mass index less than 18.5 kg per m (HR 3.03), vertical tumor dimension 20 mm or more (HR 5.84), non-well-differentiated grade tumor (HR 3.09), and operated cases with radical neck dissection (HR 4.29).

Conclusions: Surgical treatment can improve the survival outcome, whereas advanced stage and poor histological grading can worsen the overall survival. For oral tongue squamous cell carcinoma, radiotherapy was a good prognostic factor. On the contrary, a tumor with large vertical size, closed surgical margin, poor histologic grade, and radical neck dissection in the operated group were poor prognostic factors.