When pushed, medicine recognises a tripartite group of causes:
* lifestyle and nutrition
* environmental influences and pollutants
* genetic factors.
Aside from the strong association between smoking and lung cancer, the third cause is preeminent in medical education today. If your family has a history of the disease, you yourself are far more likely to succumb, and genetics is singled out as the major risk factor, especially in cases of breast cancer.
There is also the fatalistic argument that, as we are all living longer these days anyway, something has to kill us. In other words, previous generations died younger and from other causes before cancer could claim them.
As medicine is principally a study of effects rather than causes, there the debate ends, certainly within the corridors of medicine. Nevertheless, outside the medical-training colleges, it's a subject that has rightly concentrated the minds of scientists, mavericks and researchers alike.
Here are some of the more interesting theories that endeavour to tell us why we might get cancer, that tells us about the current epidemic and what, as a result, we might do about it:
The association-induction hypothesis
This idea was first proposed by Gilbert Ling in the 1950s, and was adapted by Freeman Cope in the 1970s as a possible explanation for cancer, and as a theory to support the Gerson therapy.
The theory is complex, and rooted in advanced biology. It tries to explain why cells become damaged and deteriorate, leading to degenerative diseases such as cancer, coronary heart disease and arthritis.
Our cells live in a serum that is very high in sodium and low in potassium. The serum constantly passes through each cell and, yet, the average cell contains a sodium concentration of just 7 per cent, and a potassium concentration that is 32 times greater than that of the serum.
To explain this phenomenon, biologists came up with the 'sodium pump' theory, which suggested that each cell had a pumping mechanism that somehow discards excess sodium while pulling potassium in. They also postulated that the pump's energy supply was the enzyme adenosine triphosphate (ATP) which, in turn, is fuelled by carbohydrates.
Ling disputed the pump theory and, instead, put forward the association-induction hypothesis. Put simply, Ling argued that potassium ions create a force of attraction that causes water molecules to line up its oxygen atoms in one direction and hydrogen atoms in another. Ling called this 'structured water', and suggests that water molecules are not random, but highly ordered, as exhibited by ice crystals. Water that is further away from the cell is less ordered, and so will not accept potassium ions.
A healthy cell can theoretically hold the potassium indefinitely, without using energy. Only cells that are damaged, traumatised or poisoned need energy from ATP to hold on to potassium.
Ultimately, as Freeman Cope discovered, degenerative diseases such as cancer begin when damaged cells lose the fight, and become subsumed by the sodium that surrounds them. The process is reversible only if caught in its early stages.
He saw parallels in Ling's theory with that of Dr Max Gerson, who was developing a treatment of detoxification, cleansing and strict diet to fight cancer up until his death in 1959. After studying Ling and Gerson, Cope predicted that cancer patients would benefit from a diet that was rich in potassium and low in sodium, as this would enable the weakened cells to fight the buildup of sodium (Physiol Chem Phys, 1978; 10: 449-64, 465-8).
Electromagnetic field theory
This idea - developed by Jean-Claude Mainguy, a former director at Moanda Hospital in Gabon - has a rich heritage, one that embraces eminent quantum physicists such as Erwin Schr"odinger, famous for his virtual cat mindgame, and Fritz-Albert Popp. It has had various interpretations but, fundamentally, it argues that the mechanisms of all life are governed by electromagnetic fields (EMFs) that can be either within the cell (endogenous) or outside of it (exogenous). This suggests that living systems function like transmitting and receiving radios, and that they can be structured and organised, or disorganised, by low-energy EMFs.
Mainguy decided to test the theory on five different tumour-cell strains - from cancers of the lung, breast, liver, colon and kidney. He set out to discover if it was possible to destroy these diverse cells by exposing them to pulsed EMFs.
In fact, Mainguy and his team discovered that the malignant cells were destroyed over a 48-hour exposure, and that the destructive process continued for 72 hours after the EMF pulse was switched off. All healthy cells remained unaffected.
The key discovery here was that the pulsed magnetic fields were transmitting at exactly the same frequencies as those emitted by the cancer cells, which would explain why healthy cells were unaffected.
This finding not only points to a non-invasive cancer treatment, but also suggests another reason why we get cancer in the first place (Erfahr Heilk, 1997; July: 398-404): our own electromagnetic frequencies become disturbed.
The control-factor theory
This theory argues that people are far more likely to develop cancer at times in their lives when they are not in control, or overwhelmed by events. The idea was put forward by the controversial psychologist Hans Eysenck, and has been put to the test in a series of medical trials over the years.
The first to test it was David Spiegel, at the University School of Medicine in California, in 1989. Spiegel demonstrated that women with late-stage breast cancer doubled their survival rate when they took charge of their lives with the help of psychotherapy (Lancet, 1989; 2: 888-91).
Eysenck himself tested his theory with the help of R. Grossarth-Maticek, from the University of London, by using psychotherapy to help cancer patients gain control of their lives, and so reducing their sense of helplessness. Eysenck found a 64 per cent increase in survival rates in patients with end-stage cancer (Behav Res Ther, 1991; 29: 17-21).
Michael Marmot, at University College London, has found that a sense of helplessness is a major contributory factor in cases of coronary heart disease (Lancet, 1997; 350: 235-9).
In one sense, Eysenck's theory agrees with the medical model: our personality type and, so, our inclination towards losing control of our lives, may in part be determined by our genes.
The conflict theory
The conflict theory pushes Eysenck's control theory to a new level and, as a result, has generated even more controversy and opprobrium.
Developed by Dr Ryke-Geerd Hamer, a German cancer surgeon, the idea is based on the cancer histories of 20,000 patients. After studying these records, Hamer concluded that cancer seems to attack one organ and rarely spreads to the surrounding tissue. A woman with cancer of the cervix almost never also has cancer of the uterus, for example. He also noted that the patients had suffered a psychoemotional conflict that had never been resolved.
When X-rays were taken of the patients' brains, Hamer detected a dark shadow on an area of the brain that correlated with the type of cancer in the body. There was also a correlation between the position of the shadow in the brain, the type of cancer and the type of conflict experienced by the patient.
Conflict on its own will not manifest as cancer, according to Hamer - only those conflicts that are unresolved. In these instances, the emotional reflex centre in the brain slowly breaks down and starts sending out the wrong signals to the organ with which it is connected. As a result, deformed, or cancerous, cells start to form in the organ.
Ultimately, cancer need not be treated by drugs or radiation, but with psychotherapy and resolution of the originating conflict. If this is achieved, the cancerous cells start to heal, and the shadow on the brain disappears, according to Hamer.
His theory has attracted many detractors - and his abrasive manner even more - while claims for the authenticity of his theory have only come from him rather than from legitimate, independent, research groups.
The one investigation into Hamer's theory concluded that there was no evidence whatsoever to support it (Swiss Study Group for Complementary and Alternative Methods in Cancer; document no. 01/02).
This concept, proposed by clinical psychologist Lawrence LeShan, is similar to Eysenck's and Hamer's in that it draws parallels between the disease, and personality and life events.
LeShan began his clinical research in 1952, and soon began to look into the role of the emotions as a cause of cancer. By the early 1960s, he had narrowed down the causes to personality factors and traumatic life events (J Am Soc Psychosom Med, 1962; 9: 76-82; Arch Gen Psychiatry, 1962; 6: 333-5).
From these early findings, LeShan went on to develop a form of psychotherapy that would allow patients to reenergise themselves, and to make contact with their thwarted creative and expressive selves. His later theory is encapsulated in his popular book, Cancer as a Turning Point (London: EP Dutton, 1989), and depicts cancer as a negative life force. Cancer is a turning point, or a call to arms, and an opportunity for the patient to "analyze the blocks that keep the patient from being able to live out his or her true nature", LeShan writes.
LeShan claims that patients who have undergone his form of psychotherapy have seen their tumours regress, and their life expectancy increase way beyond that expected for someone with end-stage cancer. However, like Hamer, his evidence is anecdotal, with no independent studies into the effectiveness of his work or his theory.
Nevertheless, the idea has been taken up by those doing Synergetik work in Germany, which offers intensive therapy to uncover the personality issues and mental road-blocks that we create in our lives.
The neuropeptides theory
The theories thus far have either been 'body-based' or 'mind-over-body', but this one provides a bridge between the two, and suggests that the whole body-mind debate is based on a false distinction. This theory, developed by Candace Pert, professor of physiology and biophysics at Georgetown University Medical School in Washington, DC, suggests that the body-mind functions as a single psychosomatic network of information molecules, which control our health and physiology. Our entire chemical makeup comprises neuropeptides and their receptors, says Pert, and they form the biological underpinnings of our awareness, or consciousness. They manifest as our emotions, beliefs and expectations, and they also determine how we see and engage with the world outside.
These biological messengers are intelligent and communicate information throughout the body, underpinning a vast array of conscious and unconscious activities at any one time. Intelligence is therefore not located in the brain, but is distributed evenly in the body as a whole.
Disease and cancer, according to Pert in her book Molecules of Emotion (New York: Touchstone Books, 1999), is an inability of the body to express emotion. Cancer is the result of a bottling-up of unexpressed emotions that, in turn, cause an imbalance in neuropeptides.
But, again, as with LeShan and Hamer, there has been no independent research into her theory, although it is reasonable to argue that it would be almost impossible to test in practice.
However, Pert supporters point to the pioneering work of the maverick cancer therapist Joseph Issels who, in the 1970s, showed that psychological factors play an important role in the early onset of cancer (Clin Trials J, 1970; August: 357-65).
However incomplete, most of these theories point to an energetic-emotional component of cancer requiring a far more subtle approach than the 'slash, burn and poison' approach of modern medicine. Indeed, rather than simplistically trying to cut away the tumour, we could try instead to cut away the unhealthy lifestyle and psychoemotional components of our lives. Certainly, the medical literature on spontaneous remission, which shows that those patients who make a dramatic change of outlook cure their own cancer, argues that what cancer is primarily is a disease of the soul.