Michael Bentine refused chemotherapy and went for positive thinking instead. How far can mental attitudes help to prolong life for cancer patients? Emma Haughton investigates
The comedian Michael Bentine, who died last week from prostate cancer at 74, was a man who believed in the power of positive thinking. When hormone and radiation treatment failed to check his disease, Bentine decided to fall back on his sense of humour rather than undergo the rigours of chemotherapy.

"My father believed absolutely in the healing power of laughter," says his son Richard. "He thought your outlook formed not just a mental barrier against the woes of the world, but a physical one too. You either cry about something, get depressed and crumple under, or you laugh about it, and then it hardly matters how bad it gets."

Bentine's admirable philosophy is gaining credibility within orthodox medicine. A growing body of evidence suggests that positive mental attitude not only improves the quality of life for cancer patients, but may actually help to prolong it.

When Stephen Greer, consultant psychiatrist at the Royal Marsden hospital, divided women with early breast cancer into four categories according to their reaction to their disease, he found that those who displayed a fighting spirit, as opposed to hopelessness or stoic acceptance, survived significantly longer. Across the Atlantic, Californian psychologist David Spiegel's 10-year study of 86 women with breast cancer discovered that those receiving weekly group psychotherapy, where they expressed their fear, anger and depression, survived twice as long as women receiving standard medical treatment alone.

Further research is needed to replicate and expand on these results, but the evidence so far has prompted many cancer specialists to consider whether the mind holds some sway over the course of the disease. Indeed, the idea is not new: the ancient doctor and philosopher Galen (131-201AD) noted that cancer was more common in "melancholic" than in "sanguine" patients.

"It's not a medical fact, but there are some tantalising suggestions that there's something going on here," says Professor Amanda Ramirez, psychiatric consultant with the Imperial Cancer Research Fund breast unit at Guy's. "People are now looking seriously at possible mechanisms for this effect, such as the hormonal or immunological function."

Ramirez is currently trying to replicate her earlier work, looking at the effect of negative life events on the outcome of women with breast cancer. This found that severe social stress, such as a family death, divorce, or a financial problem, was associated with an increased chance of relapse. "The effect of severe life events is most pronounced in women with cancers like breast that are sensitive to oestrogen," she says. "Stress may do something to the hormonal endocrine system or immune system which adversely affects tumour growth."

The science of psychoneuroimmunology - studying the nature of the connection between mind and body - may still be in its infancy, but it's our best hope for understanding how the way we think affects our long-term health. And it is not just concerned with how our outlook influences disease once we have succumbed.

A recent study of women treated for breast cancer at King's found they were much more likely to have experienced severe stress in the previous five years than healthy women. It seems that mental distress may actually increase the chances of cancer developing.

Greer, however, is not convinced. "The actual onset of cancer is almost certainly down to changes at the molecular level within the cell DNA. I can't see how that could be affected by immune or hormonal influences coming from the brain."

Nevertheless, he believes pyschotherapy can help those with cancer who feel particularly depressed or anxious. At the Marsden, Greer uses a cognitive- behavioural approach to examine how patients are coping with their problems, then teaches them to identify and combat negative automatic thoughts.

"It has quite a dramatic effect by showing them how to regain personal control and enjoyment from life. Many cancer patients feel they have lost control over their lives. We show them that in many areas, including treatment, they still have a lot of control and encourage them to discuss their treatment with their oncologists. I don't tell them this therapy will prolong life, but if they ask I say there's some evidence for it."

At the Bristol Cancer Help Centre, counselling is just part of a package of psychological techniques designed to help patients defeat the disease. These include visualisation, which uses mental imagery to hopefully boost the body's defence mechanisms, verbal affirmation of health, relaxation, stress management and meditation.

Bristol has since ridden the storm of a controversial study that showed patients attending the centre had a worse life expectancy than those having just orthodox treatment. The research, published in The Lancet, was discredited for failing to take into account the severity of illness of many of its clients.

The centre's methods aim to eliminate stress and take the pressure off the immune system, says centre director Dr Rosy Daniel. "Cancer patients need all sorts of information and statistics on how much difference their own efforts can make, and then the tools to go about it. But most of all we try to give hope by showing that people with cancer do live, do remit."

It's an approach that has apparently helped many. Jenny Jackson, diagnosed with primary liver cancer at 38, was given three months to live after an operation removing two-fifths of her liver failed to stop the tumour spreading. The Bristol centre was a last resort.

"I've always had a fighting spirit," she says. "If I was going to go, I wanted to go out kicking."

She found being able to talk about the fear, anxiety, and anger she had from the past helped enormously. She also started seeing a healer and counsellor, and practised relaxation and visualisation every morning. "I imagined a cleansing shower of warm liquid passing through my body and washing the cancer away." Nine years later later regular blood tests show Jenny's liver function is normal. "I'm leading a good, happy active life, but I still think of myself as in recovery. You can either give it your best shot or you give up and die."

Although Daniel has seen hundreds of similar cases, she does not advocate Bristol's techniques as an alternative to conventional treatment. The emphasis is on complementary, rather than alternative. "Most people want the best of both worlds - they will try anything that will give them a chance. But if chemotherapy, for instance, has only a 5-10 per cent chance of cure, some people want to concentrate on gaining a better quality of life for the time they've got left."

While most welcome this new emphasis on positive thinking, Chris Bradler, counselling coordinator with the cancer charity Bacup, warns that it can sometimes backfire by putting pressure on people living with cancer to have the right attitude to beat it. "It can make it difficult for cancer sufferers to acknowledge they're feeling frightened or angry about the disease. They need a lot of support to express these feelings." Those who feel they can't always accentuate the positive will be comforted to know that Greer, despite his instrumental role in attracting attention to the psychology of cancer, believes we should not give it too much emphasis. "We've shown psychological factors are significant, but they are likely to be much less influential than biological factors like the aggressiveness of the tumour," he says. "We must be careful not to exaggerate the whole thing"n