Photobiomodulation Protocols in the Analgesia of Chemotherapy-induced Oral Mucositis in Children

Inclusion Criteria:

1. Male or female children aged ≥ 3 years and < 18 years.
2. Hospitalization in an oncology or hematology department in the participating centres.
3. Patients with oropharyngeal mucositis of grade 2 or higher (WHO grading system)related to cancer chemotherapy, including conditioning for Hematopoietic Stem CellTransplantation (HSCT).
4. Written informed consent of both patient's holders of parental authority, andpatient's assent when applicable.
5. Patients affiliated to a French Social Security insurance or equivalent socialprotection.
6. Absence of any physical or psychological disability that may interfere with the LLLTapplication.

Exclusion Criteria:

1. Patients with a solid cancer lesion in the area of low-level laser application.
2. History of cervicofacial radiotherapy.
3. Application of low-level laser therapy for oral mucositis within 2 weeks prior torandomization.
4. Hyperthyroidism defined by TSH < 0.4 IU/mL at inclusion.
5. Patients susceptible to epilepsy seizure.
6. Patients with pacemaker.
7. Patients refusing to wear retinal goggles during low-level laser 1. Patients with asolid cancer lesion in the area of low-level laser application.
8. Patients protected by law (guardianship and safeguarding of justice).
9. Pregnant female patients as determined by positive serum pregnancy test at screening.
10. Lactating female patients who are actively breast feeding.
11. Participation in another clinical trial involving oral care.