Evaluation of factors associated with the risk stratification of survivorship for stage IV squamous cell carcinoma of the oral cavity: A 10-year retrospective study

Background: Oral squamous cell carcinoma (OSCC) leads to thousands of deaths every year in Taiwan. Nearly 40% of OSCC patients are diagnosed with stage IV disease, which has a poor prognosis. Multimodality treatments including surgery and adjuvant therapy have been utilized, but their treatment outcomes are generally poor. In this study, we sought to identify possible clinical impact factors that may contribute to the survival of stage IV OSCC. Methods: Data for patients with malignant neoplasms of the oral cavity registered in the Cancer Registry Database of Taipei Veterans General Hospital between 2002 and 2011 were retrieved. The study patients consisted of OSCC patients with clinical stage IV disease who had undergone a surgery and adjuvant therapy. The primary endpoints were the 5-year disease-free survival (DFS) and overall survival (OS) rates. The clinicopathological characteristics of the patients were also stratified and compared. Results: A total of 191 OSCC patients were included for retrospective analysis. The different subgroups of stage IV disease presented different treatment outcomes. The 5-year OS versus DFS rates of each subgroup were as follows: T4N0: 70.9% versus 52.6%; T1-3N23: 66.1% versus 49.8%; T4N1: 49.6% versus 31.6%; and T4N23: 40.9% versus 31.0% (p < 0.01). Patients with diabetes, moderate or poor cell differentiation, perineural invasion, and extracapsular spread presented lower 5-year OS rates (hazard ratio [HR] = 1.87, 1.65, 2.42, and 2.14, respectively), and patients with perineural invasion, positive cut margin, and extracapsular spread presented lower 5-year DFS rates (HR = 1.57, 1.62, and 1.71, respectively). Conclusion: In this study, we elucidated the different survival rates of different subgroups of stage IV OSCC following the same treatment scheme. The results of the study provide clinical physicians with references by which to evaluate prognosis and determine post-operative disease monitoring timetables based upon different characteristics.