Alteração da resistência elétrica tecidual como marcador de prognóstico de mucosite

Abstract

Head and neck cancer is one of the most aggressive type of cancer, and it is the fifth more common. The most used treatment for this disease is radiotherapy (RT) isolated or in conjunction with other therapies such as surgery and chemotherapy. Oral mucositis (OM), radiodermatitis and xerostomia are critical sequels associated with head and neck cancer, being OM the main negative outcoming. OM is harsh and debilitating, resulting in the radiotherapy protocol interruption and also impacting the health services costs. The fact that there is no OM marker makes this wound management a real challenge. The measurement of electrical quantities, as bioimpedance could be useful at this matter. When the cells go through chemical or structural transformation, changes happen in their electrical proprieties and RT creates that kind of modification in the system. This study’s goal is to investigate if the changes in the electrical tissues’ parameters are useful to determine OM development in patients suffering from head and neck cancer under radiotherapy treatment. It is a prospective randomized double-blind clinical study, with controlled cut off that followed STAND guidelines. 860 patients were assessed for eligibility and 135 were included in the clinical study. The treatment group (n=75) included patients with a confirmed histopathological diagnosis of head and neck cancer under RT treatment. The control group (n=60) were patients under RT treatment and positive diagnosis of malignant neoplasms in different areas than head and neck. The treatment group was measured weekly while under the RT to diagnose bioimpedance and evaluate the OM. The control group was only measured at the beginning of the RT treatment. As results, no difference was found in the clinical and demographical technical features. Large irradiated and non-irradiated tissues showed discrepancies from the bioimpedance parameter. The RT at the face area enlarged the local bioimpedance, resistance, reactance and phase angle, and reduced capacitance. ROC curve indicated the impedance and resistance module revealed larger particulates the other parameters. Electrical parameter evaluation at RT first week correlates with future measures. In conclusion, the electrical tissues parameters amounts measured at the first RT week are useful to foresee OM.