Pelvic ToxicityMicrOGineToxNCT07259681
Gut Microbiome in Gynecological Cancer Patients With Pelvic Toxicity: Controls Versus Ozone Treatment. (MicrOzoGineTox)
An observational study of Pelvic Toxicity and Radiation Toxicity, run by Bernardino Clavo, MD, PhD at 2 sites in Spain.
Trial summary
Patients treated for gynecological tumors with radiotherapy (RT) and/or chemotherapy (CT) frequently develop pelvic toxicity (TPIRQT), a condition that can become persistent, progressive, and refractory to standard treatments. Read more about this study
- Who is it for?
- Ages 18 years and older, women only
- Conditions the study is for
- Pelvic Toxicity, Radiation Toxicity, Chemotherapy Toxicity
- How many people
- 38 participants
- Where
- 2 sitesSpain
- Study dates
- 15 Jan 2026to 31 Mar 2028
- How long will I take part?
- 4 Months
- Phase
- Observational
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 years and older
- Women only
- No healthy volunteers
- Adult, Older adult
Study population: Patients with gynecological tumors treated with RT and/or CT with or without chronic pelvic toxicity (TPIRQT).
Who may be able to join
- Adult women (>=18 years).
- Diagnosed with gynecological tumors (any location and stage).
- Previously treated with radiotherapy and/or chemotherapy.
- Must accept and sign the specific informed consent for this study.
- Additional Inclusion Criteria for inclusion in the TPIRQT Group (Cases):
- Must present chronic TPIRQT with >= 3 months of duration after habitual symptomatic treatment.
- Must have a toxicity Grade of 2 (moderate symptoms, limiting instrumental ADL) or higher, according to the CTCAE v.5.0 scale.
Who cannot join
- Not meeting all inclusion criteria.
- Presence of active inflammatory bowel disease (e.g., Crohn's Disease, Ulcerative Colitis) or a history of major gastrointestinal resection (excluding appendectomy) that could significantly alter gut anatomy and microbiota.
- Any uncontrolled intercurrent illness or psychiatric condition that, in the investigator's opinion, would limit compliance with study requirements or interfere with the interpretation of results.
- Unwillingness or inability to provide written informed consent for study participation.
Trial locations and contacts
2 sites in 1 country. Contact the study team or a site near you to ask about taking part.
Spain2 sites, 2 recruiting
- Recruiting
Hospital Universitario de Gran Canaria Dr. Negrín, (FIISC)
Las Palmas de Gran Canaria, Las Palmas, 35019
Bernardino Clavo, MD, PhD, 34928449278, bernardinoclavo@gmail.com
Francisco Rodríguez-Esparragón, BSc, PhD, 34928449288, afrodesp@gmail.com
- Recruiting
Instituto Universitario de Enfermedades Tropicales y Salud Pública de Canarias - Universidad de La Laguna
San Cristóbal de La Laguna, Tenerife, 38296
Jacob Lorenzo-Morales, Prof, 34922318402, jmlorenz@ull.edu.es
About this study
Official title: Intestinal Microbiome Profiles in Women With Gynecological Tumors and Pelvic Toxicity Secondary to Radiotherapy and Chemotherapy: Comparison With Controls and Effect of Rectal Ozone Treatment.
Patients treated for gynecological tumors with radiotherapy (RT) and/or chemotherapy (CT) frequently develop pelvic toxicity (TPIRQT), a condition that can become persistent, progressive, and refractory to standard treatments. This toxicity, affecting the rectum (proctitis), bladder (cystitis), and vagina (mucositis), severely deteriorates quality of life. Standard options for refractory cases are limited; at our center, rectal ozone therapy is used with high rates of symptomatic improvement (66-75%). Emerging evidence suggests a link between gut microbiota and the development of TPIRQT. However, it is unknown how rectal ozone therapy may influence the gut microbiome or if this modulation is part of its therapeutic mechanism. This prospective observational study will investigate the potential relationship between gut microbiome profiles (composition and diversity), the presence and severity of TPIRQT, and the response to rectal ozone therapy.
Read the detailed description
Patients treated for gynecological tumors with radiotherapy (RT) and/or chemotherapy (CT) frequently develop pelvic toxicity (TPIRQT), a condition that can become persistent, progressive, and refractory to standard treatments. This toxicity, affecting the rectum (proctitis), bladder (cystitis), and vagina (mucositis), severely deteriorates quality of life. Standard options for refractory cases are limited; at our center, rectal ozone therapy is used with high rates of symptomatic improvement (66-75%). Emerging evidence suggests a link between gut microbiota and the development of TPIRQT. However, it is unknown how rectal ozone therapy may influence the gut microbiome or if this modulation is part of its therapeutic mechanism. This prospective observational study will investigate the potential relationship between gut microbiome profiles (composition and diversity), the presence and severity of TPIRQT, and the response to rectal ozone therapy.
- Conditions
- Pelvic Toxicity, Radiation Toxicity, Chemotherapy Toxicity, Gynecological Tumors, Radiation Proctitis, Radiation Cystitis
- Keywords
- Gut microbiota, Ozone, Ozone therapy, Gynecological tumors, Radiotherapy, Chemotherapy, Side effects, Actinic proctitis, Actinic cystitis, Quality of life, Dysbiosis
- Medical subject headings
- Radiation Injuries, Dysbiosis
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
| Study group | Role | What they receive |
|---|---|---|
| TPIRQT Group (Cases) | Patients with gynecological tumors treated with RT and/or CT who develop chronic pelvic toxicity (TPIRQT) and are referred for compassionate-use rectal ozone therapy at the Chronic Pain Unit. Samples and data will be collected before and after ozone therapy | |
| Control Group | pelvic toxicity (TPIRQT). This group will be matched by age (± 5 years) and primary tumor location. Samples and data will be collected once during a follow-up visit. |
What is being measured
The primary outcome is the main question the study is designed to answer.
Comparison of gut microbiome profile (composition and diversity) between TPIRQT and Control groups
Gut microbiome composition and diversity (from a single sample) in control patients will be compared to the baseline profile of patients with TPIRQT.
Measured: Baseline (single time point for controls, pre-ozone for cases)
Change in gut microbiome profile (composition and diversity) in patients with TPIRQT after rectal ozone therapy.
Gut microbiome composition and diversity will be analyzed from stool samples using 16S ribosomal RNA gene sequencing.
Measured: Baseline (pre-ozone therapy) , 4 Months (post-ozone therapy)
Correlation of gut microbiome profile with grade of pelvic toxicity.
Toxicity will be assessed using: i) the CTCAE v.5.0 scale from the NCI , and ii) the EORTC QLQ-CX24 questionnaire. This will be evaluated for its relationship to microbiome data.
Measured: Baseline (for Control group); Baseline, 4 Months (for TPIRQT group).
Secondary outcomes (3)
Correlation of gut microbiome profile with health-related quality of life (HRQoL).
HRQoL will be assessed using: i) the EQ-5D-5L questionnaire, and ii) the EORTC QLQ-C30 questionnaire. This will be evaluated for its relationship to microbiome data.
Measured: Baseline (for Control group); Baseline, 4 Months (for TPIRQT group).
Correlation of gut microbiome profile with anxiety and depression levels.
Anxiety and depression will be assessed using the Hospital Anxiety and Depression Scale (HADS). This will be evaluated for its relationship to microbiome data.
Measured: Baseline (for Control group); Baseline, 4 Months (for TPIRQT group).
Correlation of gut microbiome profile with biochemical markers of oxidative stress and inflammation.
Serum samples will be collected to analyze biochemical parameters of oxidative stress and inflammation and their potential relationship with gut microbiome composition.
Measured: Baseline (for Control group); Baseline, 4 Months (for TPIRQT group).
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted2 Dec 2025
- Study start15 Jan 2026
- Primary completion15 Jan 2028 (estimated)
- Study completion31 Mar 2028 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (9)Papers the sponsor has linked to this study.
- Other trials for Pelvic ToxicityStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Observational
- Observational model
- Case-control
- Time perspective
- Prospective
- Enrolment
- 38 participants (estimated)
- Target duration
- 4 Months
Sponsor and investigators
- Lead sponsor
- Bernardino Clavo, MD, PhD
- Sponsor type
- University, hospital or other
- Collaborators
- Hospital Universitario de Gran Canaria Doctor Negrín, Complejo Hospitalario Universitario Insular Materno Infantil, Fundación Canaria Instituto de Investigación Sanitaria de Canarias, Instituto Universitario de Enfermedades Tropicales y Salud Pública de Canarias, Universidad de La Laguna, Centers for International Business Education and Research
- Responsible party
- Sponsor-investigator, Bernardino Clavo, MD, PhD, Hospital Universitario de Gran Canaria Doctor Negrín
- Investigators
- Bernardino Clavo, MD, PhD, Study chair, Hospital Universitario de Gran Canaria Dr. Negrín, (FIISC), Las Palmas, SpainJacob Lorenzo-Morales, Prof, Principal investigator, Instituto Universitario de Enfermedades Tropicales y Salud Publica de Canarias, Universidad La LagunaFrancisco Rodríguez-Esparragón, BSc, PhD, Principal investigator, Hospital Universitario de Gran Canaria Dr. Negrín, (FIISC), Las Palmas, Spain
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07259681
- Sponsor's protocol ID
- 2025-436-1
- Other IDs
- PIFIISC25/52, CIGC'25/26
- Acronym
- MicrOGineTox
- Status last verified
- Sep 2026
- First submitted
- 21 Nov 2025
- Last updated
- 23 Sep 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- Yes: * It will be available (after request): Individual participant data (IPD) that underlie the results reported in further articles, after deidentification * Data will be available after publication, ending 36 months following article publication. * They will be available for investigators whose proposed use of the data has been apd by an independent review committee identified for this purpose.
Publications
Clavo B, Canovas-Molina A, Ramallo-Farina Y, Federico M, Rodriguez-Abreu D, Galvan S, Ribeiro I, Marques da Silva SC, Navarro M, Gonzalez-Beltran D, Diaz-Garrido JA, Cazorla-Rivero S, Rodriguez-Esparragon F, Serrano-Aguilar P. Effects of Ozone Treatment on Health-Related Quality of Life and Toxicity Induced by Radiotherapy and Chemotherapy in Symptomatic Cancer Survivors. Int J Environ Res Public Health. 2023 Jan 13;20(2):1479. doi: 10.3390/ijerph20021479.
PubMed 36674232Clavo B, Navarro M, Federico M, Borrelli E, Jorge IJ, Ribeiro I, Rodriguez-Melcon JI, Carames MA, Santana-Rodriguez N, Rodriguez-Esparragon F. Long-Term Results with Adjuvant Ozone Therapy in the Management of Chronic Pelvic Pain Secondary to Cancer Treatment. Pain Med. 2021 Sep 8;22(9):2138-2141. doi: 10.1093/pm/pnaa459. No abstract available.
PubMed 33738491Clavo B, Navarro M, Federico M, Borrelli E, Jorge IJ, Ribeiro I, Rodriguez-Melcon JI, Carames MA, Santana-Rodriguez N, Rodriguez-Esparragon F. Ozone Therapy in Refractory Pelvic Pain Syndromes Secondary to Cancer Treatment: A New Approach Warranting Exploration. J Palliat Med. 2021 Jan;24(1):97-102. doi: 10.1089/jpm.2019.0597. Epub 2020 May 5.
PubMed 32379556Clavo B, Santana-Rodriguez N, Llontop P, Gutierrez D, Ceballos D, Mendez C, Rovira G, Suarez G, Rey-Baltar D, Garcia-Cabrera L, Martinez-Sanchez G, Fiuza D. Ozone Therapy in the Management of Persistent Radiation-Induced Rectal Bleeding in Prostate Cancer Patients. Evid Based Complement Alternat Med. 2015;2015:480369. doi: 10.1155/2015/480369. Epub 2015 Aug 18.
PubMed 26357522Clavo B, Ceballos D, Gutierrez D, Rovira G, Suarez G, Lopez L, Pinar B, Cabezon A, Morales V, Oliva E, Fiuza D, Santana-Rodriguez N. Long-term control of refractory hemorrhagic radiation proctitis with ozone therapy. J Pain Symptom Manage. 2013 Jul;46(1):106-12. doi: 10.1016/j.jpainsymman.2012.06.017. Epub 2012 Oct 26.
PubMed 23102757Wang A, Ling Z, Yang Z, Kiela PR, Wang T, Wang C, Cao L, Geng F, Shen M, Ran X, Su Y, Cheng T, Wang J. Gut microbial dysbiosis may predict diarrhea and fatigue in patients undergoing pelvic cancer radiotherapy: a pilot study. PLoS One. 2015 May 8;10(5):e0126312. doi: 10.1371/journal.pone.0126312. eCollection 2015.
PubMed 25955845Wang L, Wang X, Zhang G, Ma Y, Zhang Q, Li Z, Ran J, Hou X, Geng Y, Yang Z, Feng S, Li C, Zhao X. The impact of pelvic radiotherapy on the gut microbiome and its role in radiation-induced diarrhoea: a systematic review. Radiat Oncol. 2021 Sep 25;16(1):187. doi: 10.1186/s13014-021-01899-y.
PubMed 34563216Li L, Yang Z, Yi Y, Song Y, Zhang W. Gut microbiota and radiation-induced injury: mechanistic insights and microbial therapies. Gut Microbes. 2025 Dec;17(1):2528429. doi: 10.1080/19490976.2025.2528429. Epub 2025 Jul 6.
PubMed 40618373Ma CY, Zhao J, Xu XT, He XL, Qin SB, Zhou JY. Predictive biomarkers in the gut microbiome and metabolome for severe acute radiation enteritis in cervical cancer radiotherapy. Discov Oncol. 2025 Jul 1;16(1):1220. doi: 10.1007/s12672-025-03077-y.
PubMed 40591053