Survival in squamous cell carcinoma of the oral cavity: Differences between pT4 N0 and other stage IVA categories

BACKGROUND. According to the American Joint Commission on Cancer (AJCC, 5^th edition) classification system, pT4 N0 oral cavity squamous cell carcinoma (OSCC) qualifies for stage IVA status, with its implied poor prognosis. However, preliminary observations suggested that patients with pT4 N0 OSCC might have better survival than other stage IVA categories. The authors sought to identify accurate prognosticators in patients with stage III/IVA OSCC. METHODS. The authors retrospectively reviewed 513 consecutive patients with stage III/IVA OSCC who were undergoing radical surgery. Survival was plotted by Kaplan-Meier analysis. RESULTS. One hundred seventy-eight patients were in stage III, and 335 were in stage IVA. The 335 stage IVA patients were divided into pT4 N0 (n = 105) and pT4 N1/TAny N2 (NO pT4 N0 M0, n = 230). By univariate analysis, 5-year neck control rates (P < .0001), distant metastases (P < .0001), disease-free survival rates (P < .0001), and overall survival rates (P < .0001) were significantly different in pT4 N0 compared with NO pT4 N0 patients. No significant difference in survival between pT4 N0 stage IVA and pstage III could be shown. Multivariate analysis for overall survival demonstrated that the following factors were independently associated with pT4 N0: tumor depth ≥35 mm, vessel invasion, lymph invasion, and perineural invasion. In contrast, tumor depth ≥25 mm, treatment with surgery alone, poor differentiation, extracapsular spread, and pathological nodal metastases (≥8 lymph nodes) were independent predictors of overall survival in NO pT4 N0. CONCLUSIONS. In patients with stage IVA OSCC (AJCC, 1997), the survival rates for pT4 N0 are better than those for NO pT4 N0 and similar to those of patients with pstage III.