‘Pressure9 Treatment Of Cancer

Press, Volume CIV, Issue 30895, 30 October 1965, Page 5

‘Pressure 9 Treatment Of Cancer

(By NOEL CARRICK of the Australian News and Information Bureau.) A RECENTLY developed technique in the treatment of cancer is being advanced by doctors in Melbourne. The technique is the bombardment of cancerous cells with a stream of highspeed X-rays from a linear accelerator while the patient is pressurised in an atmosphere of pure oxygen.

The results since the technique was introduced in 1961 have encouraged its introduction in Britain and the United States and now, almost every modern cancer treatment centre in the world is considering the use of high-pressure oxygen in conjunction with irradiation. The development of this treatment represents a swing from an idea, held for many years, that actual treatment with oxygen at high pressure was hazardous to the patient as it was thought to risk lung and brain damage. Known as oxygen baro-

therapy, the use of high-pres-sure oxygen in irradiation treatment was perfected at the Peter MacCallum clinic, Melbourne. The clinic, conducted by the Victorian Government and supported by the Cancer Institute Board, established a radio biological research unit in 1956. It was headed by a clinicial scientist, Dr. H. A. S. van den Brenk whose interest at the time was changing from surgery to radiation treatment of cancer sufferers. Part of the research unit's early work proved, after extensive tests on animals, that some cancerous growths are deficient in oxygen, making the growth resistant to radiation. At the same time, Dr. I. Churchill-Davidson, of St. Thomas’s Hospital, London, was already working along similar lines. In 1957, he installed the first barotherapy unit of this type—an inspiration to all clinics engaged in cancer treatment. However, the equipment used at St. Thomas’s was not elaborate, had many limitations, and could treat only two or three patients a day. In 1960, Dr. van den Brenk designed more elaborate and versatile hyperbarbic

oxygen apparatus which was manufactured by the Commonwealth Aircraft Corporation. Made of light aircraft alloy with heavy perspex windows, the unit, and ancillary scientific equipment at the clinic cost 122,000. It was installed and brought into use late in 1961. Since the installation of Dr. van den Brenk’s apparatus, the Peter MacCallum clinic has come to be regarded internationally as the leading centre in this type of experimental clinical research. Explaining the use of high pressure oxygen, Dr. van den Brenk said: “Cancers, as they grow in the body, tend to outgrow their oxygen supply, and oxygen concentration is reduced to low levels in various parts of the cancer. As a result of this, since irradiation for its full effectiveness in killing cancer cells depends on adequate concentrations of oxygen being present, ordinary treatments work at a disadvantage. “The only way we can get oxygen into the cancer in adequate amounts to make it much more susceptible to destruction by X-rays, is to place the patient inside pressure chambers filled with oxygen and to raise the pressure of

this chamber to three or four atmospheres, that is, to 30 to 451 b per square inch of pure oxygen.

“Then, when the patient is exposed to this oxygen, which drenches the tumor, high energy X-rays are directed to the cancer which becomes very much more sensitive.” Before treatment the patient is anaesthetised. During the period of pressurisation, careful control is maintained by a series of electronic connexions from the patient to oscillographs which show pulse, records respiration and electrical activity from the heart and other important data. During treatment, a team of two or three doctors, two nurses, and technicians are in attendance. Precision controls on the equipment allow precise positioning of the patient for treatment, greatly reducing the risk of radiation to noncancerous areas. The picture shows a patient prepared for treatment being placed in the cylinder where he is pressurised in an atmosphere of pure oxygen. Preparing the patient takes up to an hour —actual treatment under the linea accelerator only a few minutes.