Highlights ■ We developed ONCO-1, a simple tool based on tumor volume. ■ Cutoff points were defined by a CART model. ■ Tumor volume was a prognostic factor for 1-year mortality. ■ Tumor volume can to support clinical decision-making. ABSTRACT Objective: To develop a simple and accessible univariate tool based on tumor volume to predict 1-year mortality in patients with oral cavity squamous cell carcinoma. Methods: A retrospective analysis was conducted on patients with oral cavity squamous cell carcinoma included […]