Validation of the risk factors for primary control of early T-stage laryngeal, oropharyngeal, and hypopharyngeal squamous cell carcinoma by transoral surgery: a prospective observational study.

BACKGROUND: We had previously identified the following risk factors for insufficient control of early T-stage head and neck cancer by transoral surgery (TOS): (1) tumor thickness > 7 mm on enhanced computed tomography (CT), and (2) poor differentiation in pathological examination. We subsequently used a different patient cohort to validate the usefulness of these factors in determining the need for adaptation of TOS. STUDY SETTING: A prospective observational study METHODS: Patients who received TOS as a definitive treatment between April 1, 2016 and September 30, 2020 were included. Primary control rates (by single TOS and TOS alone) in relation to the above-mentioned risk factors were calculated. Overall (O), recurrence-free (RF), and disease-free (DF) survival (S) outcomes were evaluated. A combination analysis based on the number of risk factors was also performed. RESULTS: Patients with tumor thickness > 7 mm had a 2.88-fold [95% confidence interval (CI) 1.01-8.51] higher risk of incomplete primary resection by single TOS, while patients who showed poor differentiation on pathological assessments had a 13.14-fold (95% CI 3.66-47.14) higher risk of insufficient primary control by TOS alone. The 3 year OS, RFS, and DFS rates were 99%, 83%, and 63%, respectively. Patients with both risk factors had a 93.00-fold (95% CI 4.99-1732.00) higher risk of incomplete primary control by TOS alone. CONCLUSIONS: Among patients with early-stage laryngeal, oropharyngeal, and hypopharyngeal squamous cell carcinoma, primary control by TOS alone may not be achieved in patients with both risk factors, that is, tumor thickness > 7 mm as measured by enhanced CT and poor differentiation on pathological examination.