Table 1 Inclusion and exclusion criteria for patient recruitment in the DARS trial

Inclusion Criteria:

• Aged 18 or above;

• Any patient undergoing radiotherapy for HNC in the oropharynx or hypopharynx. Patients with tumour at other sites where radical radiotherapy dose is to be delivered to the pharyngeal constrictors may also be eligible;

• Stage T1-4, N0-3, M0 disease; this will be mostly histologically confirmed squamous cell carcinoma but other histological types may be eligible;

• Radiotherapy with concomitant chemotherapy (unless contraindicated) is the planned treatment;

• Creatinine clearance (≥50 mL/min prior to starting chemotherapy); not applicable for patients receiving radiotherapy alone;

• WHO performance status 0 or 1;

• Available to attend long term follow- up;

• Adequate cognitive ability to complete the MD Anderson Dysphagia Inventory (MDADI), University of Washington Quality of Life (UW-QoL) v.04 questionnaire and Performance Status Scale for Head & Neck Cancer (PSS-HN) assessments;

• Written informed consent.

Exclusion Criteria:

• Documented evidence of pre-existing swallowing dysfunction (not related to HNC);

• Previous radiotherapy to the head and neck region;

• Posterior pharyngeal wall, post- cricoid and retropharyngeal lymph node involvement;

• Lateralised tumours, requiring unilateral irradiation

• Major head and neck surgery (excluding biopsies/tonsillectomy);

• Current/previous tracheostomy placement;

• Previous or concurrent illness, which in the investigator’s opinion would interfere with completion of therapy, trial assessments or follow-up;

• Any invasive malignancy within previous 2 years (other than non-melanomatous skin carcinoma or cervical carcinoma in situ).