Chemoradiotherapy is the standard treatment for unresectable locally advanced head and neck cancer (HNC). However, malnutrition is present in 44-88% HNC patients during chemoradiotherapy, which leads to loss of skeletal muscle mass (SMM) and poor clinical outcomes. Timely assessment of SMM and early intervention of malnutrition are particularly important for HNC patients undergoing radiotherapy. However, body composition and skeletal muscle loss are not accurately reflected by the current assessment tools of malnutrition, which only measure body mass index and body weight loss.

Cone-beam CT (CBCT), a variation of traditional CT, is widely performed to ensure the appropriate position of the patients during radiotherapy. The previous study showed that measuring skeletal muscle areas and its changes using CBCT during radiotherapy is feasible. The hypothesis of this study is loss of SMM is associated with severe adverse effects in HNC patients during radiotherapy compared with body weight loss.

This is a prospective observational phase II study. Patients with locally advanced HNC scheduled to receive radical radiotherapy are prospectively enrolled in this study. CBCT and body weight are obtained before radiotherapy and once a week during radiotherapy. Severe adverse effects including grade 3-4 mucositis, dermatitis, haematological toxicity, interruption of radiotherapy, delayed chemotherapy, and unplanned admission are recorded during radiotherapy.

Inclusion Criteria:

• Histologically confirmed HNC including Oral Cavity, Oropharyngeal, Nasopharynx, Hypopharyngeal, and Laryngeal Cancers
• Clinical stage II-IVa according to the American Joint Committee of Cancer (the seventh edition)
• Eastern Cooperative Oncology Group (ECOG) performance status 0-2

Exclusion Criteria:

• Previous head and neck radiotherapy
• Previous cervical lymph node dissection
• Active infections
• Palliative treatment

Patients with locally advanced HNC scheduled to receive radical radiotherapy