Photobiomodulation (low-level laser) therapy for immediate pain relief of persistent oral ulcers in chronic graft-versus-host disease

Purpose: To determine the immediate pain-relieving effect of photobiomodulation therapy (PBMt) in patients with oral ulcers of chronic graft-versus-host disease (cGVHD) refractory to first line therapy with topical corticosteroids. Methods: This retrospective study included all patients who underwent PBMt for pain relief of refractory oral cGVHD lesions. PBMt was applied using an intraoral approach to all sites with mucosal lesions, using a 940 nm InGaAsP diode laser device, with the following parameters: pulsed modulation (duty cycle of 50%), power 0.7 W, illuminated spot size 7.1 cm², irradiance 98.6 mW/cm², and irradiation time 90 s per point. Pain was self-assessed using a 0-to-10 scale immediately before and after PBMt. Results: Data from eleven patients with a total of 56 PBMt sessions were analyzed. In 48 (85.7%) sessions, the patients reported less pain immediately after treatment, with a reduction of ≥ 50% of the initial pain level in 43 (76.8%) sessions. Mean pre- and post-treatment pain levels were 5.20 ±2.7 and 1.38 ±2.1, respectively (p < 0.001), i.e., a post-treatment reduction of 73.4% of the initial pain level. The benefits of the treatment remained for a mean of 6.50 ±5.4 days (range of 2 to 14 days). No adverse effects were reported. Conclusions: PBMt seems to be a promising treatment modality for refractory oral cGVHD lesions as a rapid pain reliever with relatively long-lasting effects.