Outcome analysis of patients with well-differentiated oral cavity squamous cell carcinoma.

The prognosis of well-differentiated oral cavity squamous cell carcinoma (OSCC) is better than less-well-differentiated neoplasms. The aim of this retrospective study was to identify prognostic factors in patients with well-differentiated OSCC. The 5-year outcomes of 467 patients with well-differentiated OSCC who underwent radical surgery and neck dissection were analyzed. In the entire cohort, the presence of pathological node metastases (pN+ vs. pN0) was an independent predictor of 5-year outcomes. In pN0 patients, tumor depth (≥8 mm) was the only independently prognostic factor for 5-year survival rates on multivariable analysis (disease-free survival [DFS], P=0.001, hazard ratio [HR]=2.634, 95% confidence interval [95% CI]=1.496-4.636; disease-specific survival [DSS], P<0.001, HR=6.794, 95% CI=2.364-19.525). In pN+ patients, level IV/V neck nodal metastases (DFS, P<0.001, HR=47.483, 95% CI=8.942-252.122; DSS, P<0.001, HR=14.301, 95% CI=5.337-38.323), and ≥3 positive nodes (DFS, P=0.037, HR=2.107, 95% CI=1.047-4.242; DSS, P=0.044, HR=2.093, 95% CI=1.020-4.295) were independently associated with 5-year outcomes. Our results suggest that a tailored treatment approach in well-differentiated OSCC patients should take into account the presence of either pN0 or pN+ disease.