Hyperbaric oxygen therapy and cancer—a review

Abstract

Hypoxia is a critical hallmark of solid tumors and involves enhanced cell survival, angiogenesis, glycolytic metabolism, and metastasis. Hyperbaric oxygen (HBO) treatment has for centuries been used to improve or cure disorders involving hypoxia and ischemia, by enhancing the amount of dissolved oxygen in the plasma and thereby increasing O2 delivery to the tissue. Studies on HBO and cancer have up to recently focused on whether enhanced oxygen acts as a cancer promoter or not. As oxygen is believed to be required for all the major processes of wound healing, one feared that the effects of HBO would be applicable to cancer tissue as well and promote cancer growth. Furthermore, one also feared that exposing patients who had been treated for cancer, to HBO, would lead to recurrence. Nevertheless, two systematic reviews on HBO and cancer have concluded that the use of HBO in patients with malignancies is considered safe. To supplement the previous reviews, we have summarized the work performed on HBO and cancer in the period 2004–2012. Based on the present as well as previous reviews, there is no evidence indicating that HBO neither acts as a stimulator of tumor growth nor as an enhancer of recurrence. On the other hand, there is evidence that implies that HBO might have tumor-inhibitory effects in certain cancer subtypes, and we thus strongly believe that we need to expand our knowledge on the effect and the mechanisms behind tumor oxygenation.

Hyperbaric oxygen and cancer: more complex than we expected

“…To date, HBO therapy has been applied in a series of diseases with potential hypoxia including decompression sickness, carbon monoxide poisoning, gas gangrene, osteomyelitis, and so on (http://en.wikipedia.org/wiki/Hyperbaric_medicine). However, cancer is not an indication for hyperbaric oxygen in both USA and China.Recently, Moen and Stuhr reviewed the evidence on the influence of HBO on cancers in past 9 years [1]. Their conclusion was consistent with two previous systemic reviews on HBO and cancer that the use of HBO in patients with malignancies is considered safe.…”

“…Recently, Moen and Stuhr reviewed the evidence on the influence of HBO on cancers in past 9 years [1]. Their conclusion was consistent with two previous systemic reviews on HBO and cancer that the use of HBO in patients with malignancies is considered safe.…”

Hypoxic microenvironment and hepatocellular carcinoma treatment

“…Both recent and previous research studies have shown that HBO can be inhibitory and reduce cancer growth in some cancer types [46] . Granowitz et al [61] show that HBO can inhibit benign and malignant human mammary epithelial cell proliferation.…”

“…One approach is to design hypoxia-activated bioreductive pro-drugs which would be activated by enzymatic reduction in hypoxic tissue; the other one is to target key molecules specifically activated in hypoxic cells, such as the most studied HIFs inhibitors. In addition, emerging new strategies such as oxygen supplement [46] and vessel normalization [47] were also developed to target the hypoxic cancers.…”

The influence of heterocyclic compound-PAMAM dendrimer complexes on evoked electrical responses in slices of hypoxic brain tissue

“…Until recently, studies on hyperbaric oxygen treatment and cancer focused on whether increased oxygen levels could act as a cancer promoter [1]. On the one hand, a decrease in the extent of the vascular network limits the metastatic opportunities of surviving tumor cells under hypoxic and ischemic conditions.…”