Analysis of the Risk Factors for Severe Oral Mucositis in Head and Neck Cancer after Chemoradiotherapy with S-1

: Radiotherapy (RT) and chemoradiotherapy (CRT) is widely accepted as the standard treatment for head and neck cancer (HNC). Oral mucositis (OM) often develops as an adverse reaction in HNC patients that receive RT or CRT involving S-1. However, little is known about the risk factors for OM in HNC patients. We retrospectively evaluated patients' pre-treatment clinical data in order to identify the risk factors for severe OM in HNC patients that are treated with RT or CRT involving S-1. We analyzed the cases of 129 patients who received RT or CRT involving S-1 for HNC. The endpoint of the survey was the occurrence of severe OM (≥grade 2). Risk factors that were significantly related to severe OM were identified using logistic regression analysis. The patients' mean age was 69.3±10.1 years, and 118 (92%) of the patients were male. The primary tumor was located in the oropharynx in 21.7% of cases. Severe OM occurred in 85.0% of cases. In the univariate analysis, the following variables were found to be associated with severe OM: age, the type of radiotherapy, disease stage, and chemotherapy. In the multivariate analysis, the location of the primary tumor and chemotherapy were identified as significant risk factors that contributed independently to the risk of severe OM (p<0.05). Our analysis suggests that cancer of the oropharynx and CRT are important risk factors for severe OM in HNC patients that undergo RT or CRT involving S-1.