Prediction of Lymph Node Metastasis by Tumor Dimension Versus Tumor Biological Properties in Head and Neck Squamous Cell Carcinomas

PURPOSE: Lymph node metastasis (LNM) is a strong prognostic factor in many solid cancers, including head and neck squamous cell carcinomas (HNSCC), and LNM can be dependent upon primary tumor biology, as well as tumor dimension. Here, we investigate the relative risk of LNM in accordance to tumor dimension and biology in HNSCC subsites. MATERIALS AND METHODS: Medical data of 295 HNSCC patients who had undergone the initial curative surgery (oral tongue 174, oropharynx 75, hypopharynx 46) were analyzed to identify the significant predictive factor for LNM. Tumor volume and thickness were set as tumor dimensional variables, and biological variables included lymphovascular, perineural invasion, and tumor differentiation. Statistical analyses were conducted to assess the predictability of LNM from variables, and subgroup analyses according to the tumor subsites. In addition, we evaluated the impacts of tumor dimension and biological variables on the treatment outcomes and survival in HNSCC subsites. RESULTS: The overall tumor dimension and biological variables had a similar impact on the prediction of LNM in HNSCC (area under the curve, 0.7682 and 0.7717). The prediction sensitivity of LNM in oral tongue cancer was mainly dependent on tumor dimension, while LNM in oroand hypo-pharynx cancers was more influenced by biological factors. Survival analyses also confirmed that biological factor was more powerful in estimating disease-free survival of hypopharyngeal cancer patients, while tumor dimension was more significant in that of oral cancer patients. CONCLUSION: Tumor dimension and biology have a significant, tumor subsite-dependent impact on the occurrence of LNM and disease-free survival in HNSCC.