This is not only false, but dangerous. People who promote this view say that cancer cells are caused by a lack of oxygen. They mutate and feed off toxic material around them. According to this view, cancer cells are a housekeeping system that keeps the body in order. This is entirely backwards. Cancer cells are normal ones which start to grow and divide out of control. They are caused when our genes become damaged, or stop working properly. This can be due to genetic changes we inherit from our parents. It can happen as a part of the ageing process. Or it can be caused by things in our environment, like chemicals in tobacco smoke, alcohol, or the ultraviolet radiation in sunlight. Once healthy cells turn into cancer cells, they start to grow into a tumour. Tumours eventually get so big that the blood vessels around them cannot provide them with enough oxygen or nutrients. We know all of this through decades of research. Scientists can see the genetic changes that transform a healthy cell into a cancerous one. It is irresponsible to tell people that cancers will protect their bodies and help them survive, when they will do exactly the opposite. It is even worse to tell them that people have brought ill health on themselves by seeking conventional treatments, when those treatments are often the only chance they have of beating the disease.