Patients Referred to the Chronic Pain Unit for Palliative Treatment With Ozone Therapy Between 2022 and 2025

Chronic Pain Unit in the absence or failure of standard treatment, or when the standard treatment is associated with high morbidity or high risk. Frequently, these patients present alterations in self-perceived health-related quality of life (HRQoL), anxiety, depression, and other symptoms. This study aims to evaluate in these patients the effect of adjuvant symptomatic/palliative ozone therapy on the HRQoL and the potential changes from baseline on several parameters after treatment. MAIN OBJECTIVES: To evaluate in these patients: 1) the clinical effect on the HRQOL of adding ozone to the standard treatment. SECONDARY OBJECTIVES: To evaluate in these patients changes from baseline on 2) anxiety and depression, 3) pain (if applicable), 4) grade of toxicity (if applicable), 5) requirements of invasive procedures for symptom management, 6) evolution of main symptoms, 7) evolution of oxidative stress and inflammation (if systemic ozone therapy). METHODOLOGY: Prospective and observational study of patients referred to our Chronic Pain Unit for symptomatic/palliative treatment with ozone therapy between 2022 and 2025. MAIN VARIABLE: 1) HRQoL through the EQ-5D-5L questionnaire SECONDARY VARIABLE: 2) anxiety and depression through the hospital anxiety/depression (HAD) questionnaire, 3) Pain through the visual analog scale (VAS), 4) grade of toxicity in cancer patients through the CTCAE v5.0 scale, 5) the number of invasive procedures required for symptom management, 6) self -reported percentage of symptom improvement, 7) biochemical parameters of oxidative stress and inflammation. Assessments at weeks: 0 (baseline), 16 (end of O3/O2 treatment, objective), 28 (12 weeks after the end of ozone), and 40 (24 weeks after the end of ozone, control) Length of treatment: as required; initially, planned 16 weeks. Follow-up: 24 weeks after finishing O3/O2 treatment. Planned length of the clinical trial: 49 months.