ABSTRACT
Introduction
The metabolic environment in ischemic and hypoxic tumors is known to contribute to cancer progression. Importantly, peculiar metabolic changes occurring in malignant cells (the increased glycolysis and the hampered Krebs cycle) may contribute to decreased antioxidant-dependent defense in ischemic and hypoxic tumors.
Areas covered
In the clinic, oxygen saturation of tumors is usually achieved by the application of water-soluble ozone and hyperbaric oxygen therapy. Tumor oxygenation has been shown to inhibit tumor growth and potentiate anti-tumor effects of chemoradiotherapy in animal experiments and the clinical setting. Tumor oxygenation could enhance anti-tumor effects achieved by tumor blood vessel occlusion or angiostatic therapy.
Expert opinion
Owing to a profound influence of ROS on both the innate and adaptive immunity, oxygen therapy, when combined simultaneously or sequentially with immunotherapeutic interventions (such as immune checkpoint inhibition, drug-induced immunostimulation, adoptive cell therapy, hyperthermia, etc.), could be considered as a novel highly-effective clinical biological approach to cancer treatment.
Article highlights
Oxidative stress-induced reactive oxygen species can preferentially damage tumor cells without significantly affecting normal cells
Oxygen therapy can potentiate anti-tumor effects of chemoradiotherapy
Oxygen therapy could be effectively combined with immunotherapy to achieve maximal anticancer effects with minimal side effects
Declaration of interest
The authors have no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, or royalties.
Reviewer disclosures
Peer reviewers on this manuscript have no relevant financial or other relationships to disclose.