Imaging nodal volume and survival in oral tongue cancer with cervical lymph node metastasis

OBJECTIVES: Oral tongue cancer is the most prevalent type of oral cavity cancer and presents the worst prognosis. With the use of TNM staging system, only the size of primary tumor and lymph node are considered. However, several studies have considered the primary tumor volume as a possible significant prognostic factor. Our study, therefore, aimed to explore the role of nodal volume from imaging as a prognostic implication. METHODS: Medical records and imaging (either from Computed Tomography (CT) or Magnetic Resonance Imaging (MRI) scan) of 70 patients diagnosed with oral tongue cancer with cervical lymph node metastasis between January 2011 and December 2016 were retrospectively reviewed. The pathological lymph node was identified, and nodal volume was measured using the Eclipse radiotherapy planning system and was further analysed for its prognostic implications, particularly on overall survival, disease-free survival, and distant metastasis-free survival. RESULTS: From A Receiver Operating Characteristic (ROC) curve analysis, the optimal cut-off value of the nodal volume was 3.95 cm(3), to predict the disease prognosis, in terms of overall survival and metastatic-free survival (p ≤ 0.001 and p = 0.005, respectively), but not the disease-free survival (p = 0.241). For the multivariable analysis, the nodal volume, but not TNM staging, was a significant prognostic factor for distant metastasis. CONCLUSIONS: In patients with oral tongue cancer and cervical lymph node metastasis, the presence of an imaging nodal volume of ≥3.95 cm(3) was a poor prognostic factor for distant metastasis. Therefore, the lymph node volume may have a potential role to adjunct with the current staging system to predict the disease prognosis. LEVEL OF EVIDENCE: 2b.