Effect of Radiological Tumor Thickness on Prognosis of Early Glottic-Squamous Cell Carcinoma Treated With Radiation

Objectives: Tumor depth of invasion is a known prognostic factor in several head and neck cancers, but data on early laryngeal squamous cell carcinoma (SCC) are sparse. In this study, we aim to determine whether radiological tumor thickness serves as a prognostic factor in early SCC of the glottis treated with radiation. Methods: One hundred thirty-two adult patients (age >18 years) underwent pretreatment computed tomography (CT) and were treated with radiation for pathologically proven early stage (T1 or T2) glottic SCC. Thirty-eight were excluded because the tumor could not be correctly identified on the CT scan, and an additional three patients because of insufficient data. Results: The final cohort consisted of 91 patients, 84 (90.3%) men and 7 (9.7%) women aged 39.86–86.53 (mean 65.55 ± 12.76) years. Mean tumor thickness was 0.59 ± 0.19 cm in patients with T1 tumors and 0.79 ± 0.21 cm in patients with T2 tumors. The optimal cutoff value for 5-year disease-free survival (DFS), using the Youden index (sensitivity: 81.2%, specificity 65.3%), was 0.7 cm. A significant advantage in 5-year overall survival (OAS) and 5-year DFS for tumor thickness of <0.7 cm (P = 0.01 and P < 0.01, respectively) was found, these findings were consistent also when each stage was examined separately (T1 vs T2). Conclusion: Radiological tumor thickness appears to significantly predict OAS and DFS in early glottic SCC patients. Implication for practice: Tumor thickness may be considered as an auxiliary aid in deciding follow-up time and frequency, proper treatment, and determining prognosis.