Analysis of risk factors of predictive local tumor control in oral cavity cancer

Background: Survival in oral cavity squamous cell carcinoma (OSCC) depends heavily on locoregional control. In this study, we sought to determine the independent prognosticators for local tumor control, disease-specific survival (DSS), and overall survival (OS) rates in a series of OSCC patients undergoing radical surgery. Methods: We retrospectively reviewed 827 consecutive OSCC patients undergoing radical surgery from January 1998 to March 2005. Postoperative radiotherapy was performed in patients with pT4 tumors, positive lymph node(s), or close margins (<= 4 mm). Local control rates and survivals were plotted using the Kaplan-Meier method. Results: On multivariate analysis (MVA), unfavorable prognostic factors for local control were pathological margins <= 7 mm (P < 0.001), pathological tumor depth >= 10 mm (P < 0.001), pathological positive lymph node(s) (P = 0.001), and the presence of betel quid chewing (P = 0.012). The same predictors, with the exception of betel quid chewing and pathological positive lymph node(s), were independently associated with DSS and OS in MVA. A prognostic scoring system was formulated by summing up the four significant local control covariates from MVA. Patients with scores of 3-4 had a significantly poorer local control rate compared to patients with scores of 0-2 (score 3 versus score 0-2: P < 0.001; score 4 versus score 0-2: P < 0.001) Conclusions: Taken together, our data suggest that pathological margins and pathological tumor depth are major independent prognosticators not only for local tumor control, but also for DSS and OS.