# Clinical Efficacy of Hydrogen Therapy on Acute Radiation Enteritis and Inflammatory Response in Patients with Cervical Cancer Undergoing Concurrent Chemoradiation Therapy.
> 子宮頸癌同時化学放射線療法における急性放射線腸炎および炎症反応に対する水素吸入の臨床的有効性


## Abstract

A prospective randomized trial enrolled 58 cervical cancer patients receiving concurrent chemoradiation therapy (CCRT), assigned to hydrogen inhalation (n=28) or control (n=30). The hydrogen group inhaled a 66.6% H2 / 33.3% O2 gas mixture at 3 L/min for 2 hours on each radiation day. Compared with controls, the hydrogen group demonstrated significantly reduced C-reactive protein, neutrophil-to-lymphocyte ratio, interleukin-6 levels, and fecal occult blood positivity. Enteritis severity grading and nutritional assessment scores were also more favorable in the hydrogen group. Tumor response evaluated by RECIST criteria did not differ between groups, indicating no interference with antitumor efficacy. No hydrogen-related adverse events were recorded, supporting the safety profile of this adjunctive approach.

### Mechanism

Inhaled molecular hydrogen is proposed to exert antioxidant and anti-inflammatory effects, reducing systemic inflammatory biomarkers such as CRP, IL-6, and neutrophil-to-lymphocyte ratio, thereby attenuating radiation-induced intestinal mucosal injury.

## Bibliographic

- **Authors**: Liu B, Bao Y, Ma J, Wang X, Feng YQ
- **Journal**: Adv Radiat Oncol
- **Year**: 2025
- **PMID**: [41020280](https://pubmed.ncbi.nlm.nih.gov/41020280/)
- **DOI**: [10.1016/j.adro.2025.101879](https://doi.org/10.1016/j.adro.2025.101879)
- **PMC**: [PMC12466126](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12466126/)
- **Study type**: human randomized controlled trial
- **Delivery route**: inhalation
- **Effect reported**: positive
- **H2 concentration**: 66.6%

## Delivery context

For inhalation applications of molecular hydrogen, the lower flammability limit (LFL) deserves careful handling. The classical 4% figure applies to closed-system mixtures; the practical inhalation-environment threshold is 10%. Even pure-hydrogen output (the UFL 75% paradox) passes through the flammable range at the air–gas boundary. High-concentration (66% / 100%) inhalers are documented in the Japanese Consumer Affairs Agency accident-information database and are not recommended.

## Safety notes

For inhalation applications of molecular hydrogen, the lower flammability limit (LFL) deserves careful handling. The classical 4% figure applies to closed-system mixtures; the practical inhalation-environment threshold is 10%. Even pure-hydrogen output (the UFL 75% paradox) passes through the flammable range at the air–gas boundary. High-concentration (66% / 100%) inhalers are documented in the Japanese Consumer Affairs Agency accident-information database and are not recommended.

See also:
- [Inhalation concentration and LFL / UFL](https://h2-papers.org/en/safety-notes/inhalation-concentration)
- [Consumer Affairs Agency accident cases](https://h2-papers.org/en/safety-notes/accident-cases)
- [LFL / UFL terminology](https://h2-papers.org/en/safety-notes/lfl-ufl-explained)
- [Inhalation safety threshold lineage](https://h2-papers.org/en/safety-notes/lineage)

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> **Cite as**: H2 Papers — PMID 41020280. https://h2-papers.org/en/papers/41020280
> **Source**: PubMed PMID [41020280](https://pubmed.ncbi.nlm.nih.gov/41020280/)