[The timing of the appearance of oral mucositis induced by concurrent chemoradiotherapy with S-1 for head and neck cancer].

Oral mucositis is a frequent adverse event in patients receiving concurrent chemoradiotherapy for head and neck cancer. Although the management of oral mucositis is essential to improve treatment completion rates, no detailed studies on the time of oral mucositis appearance have been reported. We conducted a retrospective study on the timing of the appearance of oral mucositis induced by concurrent chemoradiotherapy with S-1 for head and neck cancer. A total of 11 patients with head and neck cancer who received concurrent chemoradiotherapy with S-1 were examined. All patients developed oral mucositis within 13.8 ± 5.6 days after the initiation of radiotherapy (20.4 ± 8.1 Gy). In addition, the effects of pain-associated symptoms caused by oral mucositis on the patients' nutritional status, including reduction in caloric intake (24.4% ± 31.1%), weight loss (5.2% ± 5.2%), and duration of a regular diet (24.5 ± 17.1 days), were observed and lasted until the completion of radiation therapy. The delineation of the timing of oral mucositis appearance has become a key motivator for the patients to perform oral care proactively to limit severity and serves as a necessary index for monitoring oral health and managing pain and nutrition.