Evaluation of the Photobiomodulation Using LED Lamp for Curative Treatment of Radio-induced Mucositis.

The aim of this study is to assess the effectiveness of the treatment of radio- or radio-chemotherapy-induced early stage mucositis (stage 1 and 2) by photobiomodulation using LED lamp (PLED) in terms of controlling the mucositis assessed at the end of radiotherapy or radio-chemotherapy treatment. Other objectives of the study include: * To assess the pain evolution over-time, both overall over the evaluation period until the end of radiotherapy and at each session * To assess the needs of level 3 analgesics (morphine, oxycodone, fentanyl, hydromorphone) during the PLED protocol. * To assess the quality of life variation between inclusion and the end of treatment by radiotherapy or radio-chemotherapy. * To estimate the frequency of radiotherapy or radio-chemotherapy treatment (temporary or permanent interruption, dose modification), and eventually, the reason of this modification. * To assess the feasibility of photobiomodumation by LED (PLED) in this context. * To assess the tolerability of photobiomodumation by LED (PLED) in a short term. * To assess the frequency of the needs of nutritional support by nasogastric tube or gastrostomy tube during the PLED protocol. * To assess the weight and general condition variation during the treatment.