Tumor Thickness and Cervical Nodal Metastasis in N0 Oral Tongue Squamous Cell Carcinoma Patients: A Prospective Study

Background: Tumor Thickness (TT) plays an important role in the progress and prognosis of malignant tumors in general and oral squamous cell carcinoma in particular. Many studies have concluded that thicker tumors were associated with higher incidence of regional lymph node metastasis and as a result were associated with more lower survival rates. Aim of Study: This study aimed to evaluate relation between tumor thickness (TT) and regional lymph node metastasis in oral tongue squamous cell carcinoma patients, and to evaluate (TT) as a prognostic factor for lymph node metastasis and as an influencer in the suggested treatment plan. Materials and Methods: The study sample contained 40 patients (23 male, 17 female), who were diagnosed with stage I/II oral tongue squamous cell carcinoma. A surgical procedure for tumor excision and an excisional biopsy was performed. The tumor thickness was measured by one pathologist and the regional lymph nodes status was evaluated pathologically or radiologically or by the two methods. The study sample was divided into three groups according to tumor thickness: TT<3mm, TT (3-6mm), and TT>6mm, and the incidence of regional node metastasis in the three studied thickness groups was calculated. Tumor thickness values were compared in cases of positive regional lymph node involvement and negative regional node involvement using t-test. Results: Regional lymph node metastasis had occurred in 14 patients of our whole sample (35%) and the rates of nodal involvement in the groups of thickness <3mm, 3-6mm, and >6mm were 18.18%, 33.33%, and 47.05% respectively. The mean tumor thickness was 8.07mm in the positive lymph nodes group and 4.96 mm in the negative lymph node group with statistically significant difference at p-value<0.05. Conclusion: There was a higher incidence of regional lymph node metastasis in patients with thicker oral tongue SCC tumors, also there was a critical high incidence of nodal involvement in OTSCC tumors that exceeded 3mm thick. Prophylactic neck dissection or irradiation and close monitoring should be considered for those patients with more than 3mm thick tongue tumors.