The Effect of Photobiomodulation on Nitrite and Inflammatory Activity in Radiotherapy-Induced Oral Mucositis: A Randomized Clinical Trial.

BACKGROUND AND OBJECTIVES: To investigate pro- and anti-inflammatory cytokines and nitrite salivary levels in patients with head and neck cancer receiving photobiomodulation therapy (PBMT) associated with a Preventive Oral Care Program (POCP), for prevention and control of oral mucositis (OM) during radiotherapy (RT) associated or not with chemotherapy protocol. STUDY DESIGN/MATERIALS AND METHODS: In this randomized double-blinded clinical trial, 48 patients were randomly assigned to two groups: PBMT (n = 25) and Control (n = 23). In the PBMT group, patients were submitted to PBMT associated with the POCP. In the Control group, patients were submitted only to the POCP. Saliva samples were collected in the 1st (baseline), 7th, 14th, 21st, and 30th sessions of RT, and the levels of interleukin-6 (IL-6), IL-8, IL-10, IL-12p70, IL-1ß, and tumoral necrosis factor-α (TNF-α) were measured using the cytometric bead array. Nitrite levels were measured by colorimetric method. OM was assessed using the World Health Organization and the National Cancer Institute scales. RESULTS: Patients in the PBMT group presented less severe OM. PBMT tended to stabilize nitrite concentration levels during the RT regimen. The IL-1ß concentration was associated with higher OM scores. PBMT promoted an increase in IL-12p70, TNF-α, and IL-10 concentration. CONCLUSION: PBMT was effective in the prevention and control of severe OM, and its mechanism of action may be related to a better balance of inflammatory response that may favor injury control. Lasers Surg. Med. © 2020 Wiley Periodicals LLC.

Effect of low-level laser therapy on chemoradiotherapy-induced oral mucositis and salivary inflammatory mediators in head and neck cancer patients.

BACKGROUND AND OBJECTIVE: Oral mucositis (OM) is considered a painful and debilitating side effect in patients receiving head and neck cancer treatment. Low-level laser therapy (LLLT) proved to be effective to prevent and treat chemoradiotherapy-induced OM. The aim of this study was to evaluate the effect of LLLT in the severity of OM in patients with head and neck cancer and on the release of salivary inflammatory mediators. Clinical (score of OM severity) and biochemical parameters (concentration of inflammatory mediators, growth factors, and enzymes in saliva) were used. MATERIALS AND METHODS: Thirty patients were randomized into two groups: control and laser. LLLT was performed three times a week in the laser group, while control group received sham irradiation. OM severity was assessed according to the World Health Organization (WHO) and National Cancer Institute (NCI) scales. Pro-inflammatory and anti-inflammatory cytokines (TNF-α, IL-6, IL-1ß, IL-10, TGF-ß), growth factors (EGF, FGF, VEGF), and metalloproteinases (MMP2/TIMP2, MMP9/TIMP2) concentrations were assessed using ELISA test. Saliva samples were collected on admission, and at the 7th, 21st, and 35th sessions of radiotherapy. RESULTS: The laser group showed a reduction in the severity of OM, which coursed with significantly diminished salivary concentration of EGF and VEGF in the 7th radiotherapy session and of IL-6 and FGF in the 35th. There was a trend for reduced levels of IL-1ß, TNF-α, IL-10, TGF-ß, MMP2/TIMP2, MMP9/TIMP2 in the laser group compared to the control, however, no statistically significant differences were found. CONCLUSIONS: These findings demonstrated that LLLT was effective in reducing the severity of chemoradiotherapy-induced OM and was associated with the reduction of inflammation and repair.