All LiTEFORM patients will get the standard treatment as if they were not in the study. The difference is that half of the patients will also get the laser light therapy. To make the study fair, both the patients in the study and the research team will not know who is having the laser light therapy.

 So, if you decide to take part you will be put in one of two LiTEFORM groups.

 Group 1: Standard treatment for oral mucositis AND active laser therapy.

 Group 2: Standard treatment for oral mucositis AND inactive laser therapy. This means the machine will not actually shine a laser light into your mouth during each session.

•  You will be given up to three laser therapy sessions every week for 6 weeks.
• Before you start treatment, once a week for 6 weeks, and again at 4 months and 14 months after your last laser therapy session, you will be asked to complete some questionnaires. A member of the team will be on hand to help you.
• You will be asked to drink about half a glass of water as quickly as you can, on four occasions (before radiotherapy, on finishing radiotherapy, 4 and 14 months afterwards).