Photobiomodulation and Radio‐Epithelitis in Anal Carcinoma: A Case‐Report and Clinical Reflection on Emerging Preventive and Supportive Care Modalities

Radio-induced dermatitis, a frequent adverse effect of radiation therapy, is particularly prevalent in patients treated for anal margin carcinoma. It may present with varying severity, causing significant pain and impairment of daily mobility, influenced by both patient-related factors and treatment regimens. The standard management is challenging, largely topical and supportive, often insufficient to adequately address morbidity in severe or refractory cases. Photobiomodulation therapy using red-light and near-infrared light has been increasingly recognized in oncology supportive care; however, evidence remains limited for perianal radiation-induced skin toxicity and use prior to re-irradiation. We report the case of a 79-year-old woman treated for epidermoid carcinoma of the anal margin who developed grade 2 radiation-induced epithelitis during chemoradiotherapy, refractory to conventional topical treatments. Red-light photobiomodulation therapy (RL-PBMT, 632 nm, 67 mW/cm², 15 min per session) was initiated as supportive care. The patient experienced rapid and clinically meaningful pain reduction from the first session, followed by progressive epithelial healing over four sessions. Notably, two additional RL-PBMT sessions administered prior to a second radiotherapy cycle were associated with the complete absence of further skin toxicity. Assessment was based on clinical examination and patient-reported outcomes. This single-patient case suggests that RL-PBMT was well tolerated and may represent a useful noninvasive adjunct for managing radiation-induced dermatitis in anatomically sensitive regions. These findings are preliminary and warrant confirmation in controlled clinical studies.