Clinical outcomes of Taiwanese patients with resected squamous cell carcinoma of the upper and lower gum

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.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.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.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.