Tumor volume as a prognostic factor on the median survival in locally advanced oral cancer treated with definitive chemoradiotherapy.

Background: Surgery has been the mainstay treatment for oral cancer. Those patients, who do not receive surgery are generally treated with concurrent chemoradiotherapy (CCRT). Many factors play a role in patients' survival; tumor volume might be one of those factors. This study aims to determine the effect of the pretreatment tumor volume on the survival of oral cancer.

Methods: Retrospective study of patients with histological confirmed squamous cell carcinoma, stage III-IV oral cancer, who received definitive CCRT. Tumor volume from pretreatment computed tomography (CT) scans were reviewed and analyzed. The optimal cut-off tumor volume was evaluated by receiver operating characteristic (ROC) curve analysis.

Results: From 67 patients, half of the primary tumor sites were oral tongue. The median total tumor volume (TTV) was 73.25 cm, while the median survival was 12.5 months (95% CI 10.9-20.3). The optimal cut-off TTV =52.9 cm (P < 0.0001). The median survival of the patients, who had tumor volume <52.9 cm were 34.4 months, and for tumor volume =52.9 cm were 8.6 months (P < 0.0001). Multivariate analysis showed that TTV =52.9 cm, and intensity-modulated radiotherapy (IMRT) or volumetric modulated arc (VMAT) technique had significantly influenced on the overall survival.

Conclusions: TTV had an influence on the overall survival of locally advanced oral cancer. In addition, TTV may be considered as a factor in selecting the appropriate treatment option for these patients.