RESUMEN
PURPOSE: Oral mucositis is a painful condition that occurs in patients who undergo chemotherapy. Due to the worsening of oral mucositis, the patient may progress to a worse clinical condition and interrupt antineoplastic treatment. There is little literature on low-power laser therapy in chemotherapy for other solid tumors. The purpose of this study was to investigate whether low-level laser therapy (LLLT) applied before chemotherapy could prevent oral mucositis in patients with solid tumors. METHODS: Laser therapy was applied at a frequency of 630nm, with a dose of 2J / cm2, for the prevention of oral mucositis induced by chemotherapy specifically for non-hematological tumors. Epidemiological data, total neutrophils, general side effects, development of oral mucositis and degree, and the performance of low-power laser therapy to prevent oral mucositis were collected. The involvement of oxidative stress was evaluated by the enzyme superoxide dismutase (SOD) through blood samples, before and after chemotherapy treatments. RESULTS: LLLT in the proposed protocol is efficient in reducing the development of oral mucositis (only at grade I/II) in patients under chemotherapy and able to reduce the severity of oral mucosal lesions, in patients who developed mucositis after the use of the laser for prevention. All individuals who underwent LLLT protocol did not show a significant reduction of SOD activity after the last chemotherapy cycle. CONCLUSIONS: The prophylactic laser therapy protocol proposed by the study, defined at a frequency of 630nm, a dose of 2J / cm2, demonstrated the ability to decrease the occurrence of oral mucositis in patients undergoing chemotherapy protocols to solid tumors. This effect could be related to preserved SOD activity, as it was observed that oral mucositis is related to leukopenia and reduced SOD activity and LLLT protocol prevented the decrease of SOD activity.