Glioblastoma multiforme (GBM) (also called glioblastoma) is a fast-growing glioma that develops from star-shaped glial cells (astrocytes and oligodendrocytes) that support the health of the nerve cells within the brain. GBM is often referred to as a grade IV astrocytoma. These are the most invasive type of glial tumours, rapidly growing and commonly spreading into nearby brain tissue. GBMs can arise in the brain “de novo” or evolve from lower-grade astrocytomas or oligodendrogliomas. In adults, GBM occurs most often in the cerebral hemispheres, especially in the frontal and temporal lobes of the brain. GBM is a devastating brain cancer that typically results in death in the first 15 months after diagnosis. Glioblastoma cells have more genetic abnormalities than the cells of other types of astrocytoma brain cancer. As a result, researchers believe that several different genetic mutations are involved in the development of these cancers. These genetic mutations can be caused by: Inherited DNA defects.

Hyperbaric Oxygen Therapy increases oxygen to the tissue and increases the effectiveness of radiation and chemotherapy.Limited clinical trials and suggest that radiotherapy immediately after HBOT enhances the effects of radiotherapy in some cases. HBOT also is able to strengthen the anti-tumor effect of chemotherapy when applied together. Overall, HBOT is well tolerated in the GBM patients and does not significantly increase toxicity. HBOT applied by itself as a curative strategy against GBM and other cancer forms is controversial. Advantages of HBOT as an adjunct to Radiotherapy Combination of HBO with radiotherapy is considered to be useful for the following reasons:

• It allows a more uniform kill by improving the oxygenation, and therefore the radio sensitivity, at the cellular level.
• It is useful as an adjunct to surgical repair after radiation.
• HBO is considered to be the most effective method for counteracting tumor hypoxia for enhancing the effect of radiotherapy on cancer.

• HBO is also a useful therapy for radiation-induced necrosis of normal tissues.
• In a controlled study of patients with or without HBO, the survival has shown to be higher in the HBO control group. The greatest advantage was seen in the less advanced tumors).
• In experimental bladder tumor, tissue oxygen tension has been shown to be higher in the bladder trigone region. HBO was shown to enhance the effect of combined chemotherapy and radiotherapy in this model.