The aim of this feasibility, prospective, single-center trial is to compare an intra-oral Photobiomodulation (PBM) via the Caremin650TM device (NeoMedLight) and a transcutaneous PBM via the ATP 38® device (Swiss Bio Innov) in patients treated with radiotherapy or chemoradiotherapy for cancer of the oropharynx or oral cavity. PBM session will be carried out first at the rate of two sessions per week for preventive purposes, and then, in case of occurence of grade 1 mucositis, three sessions per week with curative purpose.

Oral mucositis (OM) is defined as damage to the mucosa of the oral cavity; it can be due to chemotherapy or radiotherapy. The incidence of OM is 59 to 100% according to studies in patients with oral cavity or oropharyngeal cancer receiving radiotherapy.

Clinically, OM is characterized by erythematous changes in the mucosa, which can progress to oral ulcerations. It can significantly alter the quality of life, the ability to eat, cause weight loss in patients and interfere with the proper realization of anti-tumoral treatment. Additionally, OM may increase the risk of bacteremia and sepsis in immunocompromised patients.

So far, effective management strategies for OM and associated pain are still insufficient. A wide variety of topical and oral agents are available, but effectiveness is still lacking.

Photobiomodulation (PBM) therapy involves the application of visible or infrared light produced by laser diodes or light-emitting diodes (LEDs) to stimulate wound healing, reduce inflammation, and decrease pain.

PBM can be performed in two main ways: intraoral and transcutaneous. Intraoral PBM involves applying red or near-infrared light directly in contact with the oral mucosa, while transcutaneous PBM involves the application of infrared radiation to the skin. Both techniques have shown their effectiveness. Numerous trials have evaluated the impact of PBM in radiomucositis but its use in clinical practice is to date not widespread and heterogeneous.

Inclusion Criteria:

• Adult patient (18 years old and older);
• Patients with oral cavity or oropharynx cancer treated with radiotherapy or chemo-radiotherapy;
• Karnofsky Performance Status > 60%;
• Able to understand French;
• With signed informed consent;
• Affiliated to French Health Security Insurance

Exclusion Criteria:

• Allergy to polyurethanes;
• Head and Neck tumors that are localized to other sites than oral cavity or oropharynx
• Previous irradiation of Head and Neck (whatever the time lapse between the two irradiations)
• Pregnant and breastfeeding woman;
• Patients with pacemaker device
• Epileptic patients;
• Concomitant treatment or treatment within the 7 days before inclusion with one of several drugs from the following list: fluoroquinolones, cycline, methotrexate, auranofin
• Patients with ophthalmic diseases (such as maculopathy, retinopathy, glaucoma and cataract, retinal damage)
• Patients under judicial protection