Introduction: Radiation-induced oral mucositis (RIOM) may cause severe pain and impaired quality of life during head and neck radiotherapy (RT). Preventive photobiomodulation (PBM) has shown promising clinical benefits. Materials and Methods: Eligible patients had oropharyngeal or oral cavity cancer and were opioid-naïve at the start of curative-intent RT. Patients in the PBM group were treated between 2020 and 2023. PBM was applied to the entire oral mucosa at 2.25 J/cm 2 ( λ = 660 nm). Extraoral PBM was delivered using an LED cluster device at 6 J/cm 2 ( λ = 810 nm) to target the pharyngolaryngeal mucosa. PBM was administered three times per week by trained radiation therapists. A historical control cohort treated between 2012 and 2019 was matched 1:1 based on tumor site, concurrent systemic therapy, and prior surgery. The primary objective was to evaluate differences in daily morphine consumption at the end of RT according to the preventive use of thrice-weekly oral PBM in patients receiving curative-intent RT for head and neck cancer. Results: A total of 280 patients were included: 45% had oral cavity cancers, 43% were treated postoperatively, and 42% received RT without systemic therapy. Morphine use was significantly lower in the PBM group at the end of RT (22.9 vs. 37.4 mg/day; p = 0.002) and 1 month post-RT (10.3 vs. 27.2 mg/day; p = 0.0001). No morphine was required in 60% of PBM patients compared with 47% of controls. PBM appeared particularly beneficial in oropharyngeal cancer, in patients receiving definitive RT, and with concurrent treatment. In contrast, rates of grade 3–4 RIOM at the end of RT were identical (63% in both groups), and grade 3–4 mucositis-free survival did not differ ( p = 0.99). Conclusion: In this large matched cohort, preventive PBM reduced morphine consumption during and after RT, supporting its use to alleviate RIOM-related pain in head and neck cancer patients.
Giraud et al. (2026) studied this question.