Assessment of the Impact of Increased Production of Reactive Oxygen Species Produced During Repeated Sessions of Hyperbaric Oxygen Therapy in Patients Undergoing Radiotherapy for Neoplasia, on the Occurrence of DNA Damage

Hyperbaric Oxygen Therapy (HBOT) is a treatment involving the administration of oxygen at pressures higher than atmospheric pressure, with numerous potential indications such as radiation-induced tissue damage, chronic wounds, and more. HBOT significantly increases the amount of dissolved oxygen in tissues, thereby promoting wound healing.

However, this "hyperoxygenation" may also exert toxic effects, particularly through the production of reactive oxygen species (ROS), which can induce DNA damage and potentially promote mutagenesis, thereby increasing long-term neoplastic risk.

A single HBOT session is associated with a significant increase in ROS production, which may persist for up to 48 hours post-exposure, and is also linked to DNA damage. DNA repair is typically a rapid process, with the activation of protective mechanisms.

The effects of repeated HBOT sessions remain a matter of debate. Reported outcomes range from attenuation of genotoxicity, to exacerbation of DNA damage, or no effect at all (8). In patients with cancer or comorbidities associated with impaired DNA repair capacity, repeated HBOT could be more detrimental, potentially increasing genotoxic effects and cancer risk. This increased oxygen susceptibility in cancer patients has already been observed in normobaric conditions during abdominal surgery, where hyperoxygenation strategies were associated with increased mortality in this subgroup.

A potential pro-carcinogenic effect of HBOT in cancer patients has also been suggested in some case series, though not confirmed by larger studies.

Current literature on HBOT safety remains generally reassuring; however, the possibility of DNA damage and its potential long-term genotoxic consequences cannot be entirely excluded. This question is of particular importance given that many primary indications for HBOT involve patients with a history of malignancy or active cancer