Impact of tumor-stroma ratio in oral squamous cell carcinoma prognosis

Abstract

Oral cancer, mainly represented by the squamous cell carcinoma (OSCC), is globally the 10th most prevalent cancer worldwide, with a global annual incidence of approximately 300,000 new cases. Despite advances in the diagnosis and treatment options, the prognosis of patients with OSCC has remained virtually unchanged over recent decades, remaining at 50% over 5 years. Therefore, the identification of factors (novel biomarkers) that better represent the biological behavior of the tumor cells is necessary to improve the treatment and prognosis of patients with this tumor. In the last years, by setting international multicenter collaborations, we have conducted a series of studies searching for histopathological markers that can differentiate tumors that show a more aggressive behavior. Besides the new scoring system for OSCC histological grading denominated BD system, which is based on the presence of tumor cell nests (buds) in the invasive front (B = budding) and on depth of invasion (D = depth of invasion), we have recently revealed that tumor-stroma ratio (TSR), within the concept of a simple histological marker, is associated with an unfavorable prognosis for patients with OSCC at early stage. This study also showed that the association of TSR and BD scores improves the prognostic discrimination ability compared with them isolately. Although TSR was associated with cancers from other locations, only one study explored this prognostic marker in OSCCs. The aim of this study is to evaluate the prognostic value of TSR in a series of 150 OSCCs of patients diagnosed and treated in 2 reference Hospitals. This sample will be also scored with BD system and combined analysis (TSR and BD) will be performed. Scoring will be independently carried out by 3 calibrated observers, allowing subsequent determination of intra- and inter-observer degree of agreement. Correlations between TSR and clinic pathological parameters, including BD system, and survival will be performed. The results of this study can confirm the prognostic value of TSR, validating it as a novel prognostic tool for OSCCs.