What is a hyperbaric chamber? It is a device that a person enters in order to have oxygen under pressure given to them.
There is definite research showing the benefits of hyperbaric for a variety of complaints from decubitus ulcers (bedsores) and diabetic non-healing wounds to cancer treatment [1, 2] For cancer treatment, oxygen makes cancer cells weaker and less resistant to treatment. [3, 4]
Dominic D’Agostino of the University of South Florida has done research for the Department of Defense for work with Navy SEALS. His work shows that a ketogenic diet and hyperbaric oxygen therapy prolong survival in mice with systemic metastatic cancer.  In fact, this work shows a ketogenic diet with hyperbaric oxygen stops the tumor growth progression.
But a good hard shell hyperbaric chamber will cost around $75,000. (That’s the price of a very nice new BMW!) Taking time out of the day to drive to a clinic and paying for the use of a hard shell? Who has that much time? So what are the alternatives?
Manfred von Ardenne, a student of Otto Warburg, investigated the delivery of oxygen to the patient in what he called the “Oxygen Multistep Therapy” or O2MT which evolved into at home therapy called “Exercise With Oxygen Therapy” or EWOT. Dr. Ardenne found that this therapy stimulated the immune system, impacts microcirculation, increases oxygen status and improves the overall energetic status. 
This work is so impressive that Warburg wrote a letter to von Ardenne stating: “In these last few years you have certainly reached the peak of cancer research; I certainly know of no single book in the whole of cancer research in which anyone else has tackled the therapy problem with the same energy and breadth. My instinct tells me that, in the long run, your victory is certain.”