It is estimated that there will be 670,000 new cases of cancer worldwide in 2020-2022 and it is known that the most commonly instituted treatments in cancer are chemotherapy, radiotherapy and surgery. However, these treatments have undesirable side effects, such as Radiodermatitis after Radiotherapy (RD). In fact, the prevalence of possible side effects after radiotherapy is estimated to be 80 to 90%. Radiotherapy complications are associated with a negative impact on patients' quality of life and few supportive measures are available for such complications. Thus, the management of these side effects has been studied in the literature until the present day. On the other hand, Photobiomodulation (PBM) has an important role in wound repair and tissue regeneration, as it influences the different phases of lesion resolution, including the inflammatory phase, the proliferative phase and the remodeling phase. Thus, the aim of this study is to report a case series of Head and Neck Cancer Patients diagnosed with radiotherapy-induced acute radiodermatitis treated with PBM and/or PDT. This is a case series report and the study data will be extracted from the medical records of threee head and neck cancer patients with grade 2 to 4 followed up from 2022 at the Laser Therapy Outpatient Clinic in a Universitarian Hospital. The outcomes are the size of the lesion, the presence of pain assessed by the Visual Analogue Scale (VAS) and the RTOG Scale (Radiation Therapy Oncology Group Scale) to assess the degree of Radiodermatitis before and after PBM/PDT therapy. Data with positive or negative results will be reported.

It is estimated that there will be 670,000 new cases of cancer worldwide in 2020-2022 and it is known that the most commonly instituted treatments in cancer are chemotherapy, radiotherapy and surgery. However, these treatments have undesirable side effects, such as Radiodermatitis after Radiotherapy (RD). In fact, the prevalence of possible side effects after radiotherapy is estimated to be 80 to 90%. Radiotherapy complications are associated with a negative impact on patients' quality of life and few supportive measures are available for such complications. Thus, the management of these side effects has been studied in the literature until the present day. On the other hand, Photobiomodulation (PBM) has an important role in wound repair and tissue regeneration, as it influences the different phases of lesion resolution, including the inflammatory phase, the proliferative phase and the remodeling phase. Thus, the aim of this study is to report a case series of Head and Neck Cancer Patients diagnosed with radiotherapy-induced acute radiodermatitis Grade 2 to 4, treated with PBM/PDT. This is a case series report and the study data will be extracted from the medical records of three head and neck cancer patients with grade 2 to 4 RD followed up from 2022 at the Laser Therapy Outpatient Clinic in a Universitarian Hospital. The outcomes are the size of the lesion, the presence of pain assessed by the Visual Analogue Scale (VAS) and the RTOG Scale (Radiation Therapy Oncology Group Scale) to assess the degree of Radiodermatitis before and after PBM/PDT therapy. The assessment will be done pre-treatment, weekly during PBM therapy and post-treatment. The PBM therapy are focal low-level laser therapy, 1 to 3 Joules per point, depending on the degree of pain, wavelength 630 to 830 nm, transcutaneously on the surface of the tissue injured by radiotherapy, three times a week during radiotherapy treatment and two more applications after the end of radiotherapy Data with positive or negative results will be reported.

Inclusion Criteria:

• Patients with diagnosis of head or neck cancer
• Must be undergoing Radiotherapy
• Must have a diagnosis of Grade II, III or IV radiodermatitis by RTOG Scale, made during the follow-up of the patient in their routine treatment at the hospital by the oncology team
• who do not present clinical signs of another pathology that justifies the presence of the dermis lesion.

Exclusion Criteria:

• Critical clinical states;
• End-of-life or palliative care;
• Patients with skin lesions of another cause even when undergoing RT;
• Patients referred to the laser clinic for the prevention of radiodermatitis without the active RD lesion.
• Patients who have used another photobiomodulation therapy protocol foresaw injury not related to the study.
• All contraindications already defined in the routine referral to the outpatient clinic (patients who have an active tumor at the site to be irradiated; individuals with a history of photosensitivity to photonic or light therapy;patients who have undiagnosed lesions in the treatment region; patients using topical photosensitizing medications or creams;cognitive, psychiatric or neurological changes that prevent the free understanding of the PBM therapy

outpatient cancer patients undergoing radiotherapy and who show signs of radiodermatitis RTOG II, III or IV