(0734) Survival Impact of Depth of Invasion in Nodal-Negative Oral Tongue Cancer Undergoing Radical Surgery Along

Introduction: This study aims to assess the significance of depth of invasion (DOI) in patients with nodal-negative oral tongue squamous cell carcinoma (OTSCC) treated solely with radical surgery.

Methods: Patients with nodal-negative OTSCC who underwent radical surgery with sufficient margins and did not receive adjuvant therapy were enrolled from 2005 to 2017. The primary outcomes were all-cause mortality (ACM), cancer-specific mortality (CSM), local recurrence (LR), and regional recurrence (RR). A nomogram, utilizing DOI, was developed for predicting 5-year overall survival.

Results: A total of 243 patients were included in this study. Univariate analysis revealed DOI as the sole significant predictive factor in LR (HR 1.081, 95% CI 1.021–1.145, p = 0.008). Each unit increase in DOI was associated with an elevated hazard of ACM (HR 1.07, 95% CI 1.03–1.111, p < 0.001) and CSM (HR 1.087, 95% CI 1.04–1.136, p < 0.001) but not in RR (HR 1.042, 95% CI 0.986–1.102, p = 0.144). In multivariate analysis, after adjusting for other variables, DOI remained significant in overall death and cancer-specific death. Furthermore, the concordance index of the proposed nomogram model for 5-year OS prediction increased to 0.702 with the inclusion of DOI in the calculation.

Conclusions: DOI was associated with an increased hazard of LR, CSM and ACM in patients with nodal negative OTSCC managed by radical surgery alone.