Patients Referred to the Chronic Pain Unit for Palliative Treatment With Ozone Therapy Between 2026 and 2029.

Prospective and Observational Study of Patients Referred to the Chronic Pain Unit for Palliative Treatment With Ozone Therapy Between 2026 and 2029. Prospective Study EPOOzo-2.

The main objective of this study is to analyze the impact on the health-related quality of life of patients with refractory symptoms who have been referred to the Dr. Negrín University Hospital Chronic Pain Unit for adjuvant palliative treatment with ozone therapy between January 2026 and December 2029. Additionally, the study aims to evaluate several specific symptoms, hyperspectral and thermal images, non-invasive clinical parameters related to the Autonomic Nervous System (such as heart rate variability, electrochemical skin conductance, and vibration perception thresholds), oxidative stress and inflammatory parameters, and gut microbiota composition.

Patients are referred to the 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 such as radiation-induced pelvic toxicity or chemotherapy-induced peripheral neuropathy (CIPN).

This prospective observational study (EPOOzo-2) aims to evaluate the effect of adjuvant symptomatic/palliative ozone therapy on HRQoL and potential changes from baseline. Specifically, it incorporates new non-invasive technologies to objectively assess microcirculation, neuropathy and autonomic regulation.

Main Objectives:

1. Analyze the impact on HRQoL of patients with refractory symptoms treated with ozone.

Secondary Objectives: Depending on the clinical case, analyze the impact of ozone treatment on: 2. Anxiety and depression. 3. Treated symptoms (e.g., pain, paresthesia). 4. Fatigue. 5. Toxicity grade (in cancer patients). 6. Non-invasive clinical parameters related to the Autonomic Nervous System (central and peripheral) and somatosensory function. 7. Biochemical parameters and gut microbiome analysis (in patients with systemic/rectal ozone).

Methodology: Prospective and observational study of patients referred for symptomatic/palliative ozone therapy between January 2026 and December 2029.

Assessments at weeks: 0 (baseline), 16 (end of O3/O2 treatment), 28 (12 weeks after the end of ozone), and 40 (24 weeks after the end of ozone).

Inclusion Criteria:

• 1. Adults ≥ 18 years old.
• 2. Patients referred to the Chronic Pain Unit of the Dr. Negrín University Hospital for symptomatic/palliative treatment with ozone therapy because conventional treatment does not exist, has failed, has offered insufficient results, or is associated with high risk/morbidity.
• 3. After evaluation of symptoms and patients, it exists a potential benefit of adding ozone treatment to the current treatment.
• 4. Patients have no contraindications for ozone treatment.
• 5. Patients must sign the specific Informed Consent for this study and for the ozone treatment.

Exclusion Criteria:

• 1. Age < 18 years old.
• 2. Psychiatric illness or social situations that would limit compliance with study requirements.

Contraindication or disability to attend scheduled treatments.

• 3. Contraindication or disability to attend scheduled treatments.
• 4. Uncontrolled clinical conditions (e.g., severe heart failure, massive hemorrhage, status epilepticus).
• 5. Life expectancy < 6 months.
• 6. Known allergy to ozone.
• 7. Hemochromatosis (for systemic ozone treatment).
• 8. Pregnancy (for systemic ozone treatment).
• 9. Significant Glucose-6-Phosphate Dehydrogenase deficiency (Favism) (for systemic ozone treatment).
• 10. Patients who do not meet the inclusion criteria.