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The aim of this study was to perform a systematic review to evaluate the impact of photobiomodulation therapy (PBMT) for the prevention of oral mucositis (OM) on the quality of life (QoL) of patients with head and neck cancer (HNC) undergoing radiation therapy. This study followed the Preferred Reporting Items for Systematic Reviews and Meta-Analysis guidelines. The search strategy was performed in five electronic databases (Cochrane, Embase, PubMed, Scopus, and Web of Science). The included studies assessed the QoL of patients undergoing radiation therapy (RT) for HNC and undergoing PBMT for the management of OM. Seven articles met the eligibility criteria. Data extraction was performed in the selected studies including the PBMT parameters (active medium, application procedure, wavelength, fluence, power, irradiance, irradiation time, spot size, energy per point, schedule of irradiation, and total energy). The included studies were qualitatively analyzed, and descriptive analyses were performed. Also, summary results were evaluated for group comparison analysis. All included studies confirmed a decrease in the QoL of the patients that developed OM throughout the RT progress when compared to baseline. Of the informed cases, most of the patients who received PBMT showed grades 1 and 2 OM, while the control group showed more individuals with severe forms of OM (grades 3 and 4). In this sense, patients submitted to PBMT reported better QoL at the end of the treatment compared with the control group. PBMT used for the management of OM preserves the QoL of patients with head and neck cancer., (© 2023. The Author(s), under exclusive licence to Springer-Verlag London Ltd., part of Springer Nature.)

The aim of this study was to evaluate the effect of photobiomodulation therapy (PBMT) on histone 3 acetylation (acH3) and NF-κB expression during oral ulcer healing. A total of 48 male Wistar rats were divided into control group (CG) and PBMT group (n = 24 each). Traumatic ulcers were created in the dorsum of the rats' tongue with a punch tool. Irradiation with InGaAlP laser, 660 nm, 40 mW, 0.04 cm 2 spot size, 4 J/cm 2 , 4 s, and 0.16 J per spot was performed once a day in close contact for 10 consecutive days. CG received only daily handling. Rats were euthanized on days 3, 5, and 10 (n = 8) and were monitored daily to assess wound status. Immunohistochemical analysis for acH3 and NF-κB detection was performed. One thousand epithelial cells were counted, and mean acH3- and NF-κB-positive cells were calculated and compared between the groups. PBMT accelerated the repair of oral ulcers. On day 3, PBMT showed significantly higher means for acH3- and NF-κB-positive cells than CG. On day 5, no difference was observed between the groups concerning both markers. On day 10, PBMT presented lower acH3 and NF-κB means than the control group. We concluded that PBMT stimulates keratinocyte migration in the early stage of oral wound healing and keratinocyte differentiation at the final stage by modulating histone acetylation and NF-κB expression.

Oral mucositis (OM) is an adverse side effect among hematopoietic stem cell transplantation (HSCT) recipients. The objective of this retrospective study was to evaluate the preventive effect of photobiomodulation (PBM) applied three times per week versus seven times per week in patients undergoing HSCT. The risk factors related to the incidence and severity of OM were also assessed. This was a retrospective study that evaluated 99 HSCT recipients who received different PBM protocols. Group I received three sessions per week, and group II received daily treatment. PBM was applied using a continuous-wave diode laser (InGaAlP; MM Optics, São Carlos, SP, Brazil) at a wavelength of 660 nm (visible-red) and a total radiant energy of 0.24 J per point. The baseline disease, type of transplant, type of conditioning, prophylaxis against graft-versus-host disease, OM grade, absolute leukocyte and platelet counts, and levels of liver and renal function markers were collected from medical records. The patients' age ranged from 13 to 71 years (mean/SD, 40.54 ± 16.45). No significant difference was observed between groups I and II regarding sex, age, ethnic, diagnosis, donor type, and conditioning treatment. Both PBM protocols were equally efficient in preventing OM (p = 0.34, ANOVA). Independent of the PBM protocol used, patients who received allogeneic transplant (p < 0.01-Fischer's exact test), total body irradiation (TBI-12Gy) (p = 0.01-chi-square test), busulfan + cyclophosphamide (p < 0.01-chi-square test), or methotrexate-containing regimens (p < 0.01-Fischer's exact test) demonstrated higher OM incidence and severity. Myelosuppression (p < 0.01-Mann-Whitney test) and impaired renal function (p = 0.02-Mann-Whitney test) were also considered risk factors for OM. Based on this retrospective data, PBM was effective in preventing OM in patients undergoing HSCT even when it was applied three times a week. A prospective study might be necessary to confirm these findings.