OP184: Tumor thickness: Cut-off value at risk for positive nodes in cT1-2N0 squamous cell carcinoma of the oral tongue and floor of the mouth

Abstract

Purpose The presence of positive nodes in the neck is an important prognostic factor in oral squamous cell carcinoma. The aim of this study was to determine the optimal cut-off value of tumor thickness (TT) and a clinically relevant risk of positive nodes in patients cN0. Material and methods We retrospectively reviewed 108 cT1-2N0 oral tongue and floor of the mouth squamous cell carcinoma who had primary surgery between 1994 and 2012. Results Mean age was 57,7 years (23–95). The male:female ratio was 2.7:1. Oral tongue was involved in 64 (59.3 %) patients, and floor of the mouth in 44 (40.7%) patients. Selective neck dissection (SND) I-III was performed unilaterally in 34 patients and bilaterally in 39; SND I-IV was performed unilaterally in 27 patients and bilaterally in two; a combination of SND I-III and I-IV was performed in six patients. Pathologically invaded nodes were detected in 28.7% patients (31/108) and 12/31 had extracapsular spread. TT ranged from 1 mm to 24 mm (mean 8.2 mm) with a mean value of 6.6 mm (1–22) in the pN0 group ( n = 77) and 11.9 mm (5–24) in the pN + group ( n = 31). Patients were found to be pN+ in 0% (0/28), 31.8% (14/44), 31.8% (7/22) and 71.4% (10/14) of cases when TT was Conclusions Based on our retrospective data, the optimal TT cut-off point for prompting prophylactic neck dissection is 5 mm. However, larger prospective studies bases on TT measures on preoperative imaging techniques (e.g. MRI or US) are needed before to propose a wait-and-see policy.