ABSTRACT
OBJECTIVES: This large-scale cohort study was designed to compare the clinical outcomes of Taiwanese patients with squamous cell carcinoma (SCC) of the upper versus lower gum. METHODS: Between 2004 and 2017, we identified 4244 patients with first primary SCC of the gum (694 upper gum; 3550 lower gum) who were treated with surgery either with or without adjuvant therapy. Of them, 1990 patients (329 upper gum; 1661 lower gum) enrolled from 2011 to 2017 had a higher number of histopathological variables and entered subgroup analyses. Five-year disease-specific survival (DSS) and overall survival (OS) rates served as outcome measures. RESULTS: The 5-year DSS and OS rates of patients with upper gum SCC were lower than those of cases with lower gum SCC (65%/74%, p < 0.0001; and 55%/65%, respectively, p < 0.0001). Compared with lower gum SCC, upper gum SCC had a higher prevalence of the following variables: female sex, age ≥ 65 years, pNx (without neck dissection), no-betel chewing (2011-2017), no-smoking (2011-2017), and margin status ≤ 4 mm (positive and close margins, 2011-2017). On multivariable analysis, gum subsite (upper versus lower), age (≥65 versus < 65 years), pT (T3 - 4 versus T1 - 2), pN (N1 - 3 versus N0/Nx), depth (≥10 mm versus < 10 mm, 2011-2017), ENE (present versus absent, 2011-2017), and margins (≤4 mm versus > 4 mm 2011-2017, only DSS) were identified as independent adverse prognostic factors for 5-year DSS and OS. CONCLUSIONS: Compared to lower gum SCC, upper gum SCC had less favorable 5-year outcomes. Wide resection margins are recommended to improve prognosis of upper gum SCC.
