Friday, April 29, 2005

The rise of cancer

'Worldwide cancer rates "double"', declared BBC News, reporting on new statistics compiled by Cancer Research UK. These show that the number of cases of lung cancer has risen from 600,000 in 1975, to 1.4million today, and cases of breast cancer have risen from 500,000 to 1.1million in the same period. While the report notes the older and larger population today, Cancer Research also emphasised the role of lifestyle in the increase. Professor John Toy, Cancer Research UK's medical director, said: 'These statistics show that cancer is still essentially a major disease of the developed world. Only four per cent of deaths in Africa are due to cancer, compared to 19 per cent in Europe. The developing world can learn from past mistakes: tackling the smoking habit, for example, would minimise future lung cancer cases and substantially reduce the future cancer burden in developing countries.'

Perversely, this increase in cancer diagnoses could be interpreted as a cause for celebration. Cancer is overwhelming a disease of old age. Over 80 per cent of cancer deaths in the UK are in people over the age of 65. If more people are developing cancer, it is because they now live long enough to do so. As the report notes, 'World life expectancy at birth is now at 65 years, having increased by a remarkable 20 years since 1950. By 2050, life expectancy is expected to exceed 76 years'.

Nor are all forms of cancer on the increase. Cancer Research UK notes that 'rates of stomach cancer, the most common type of cancer in 1975, are falling in association with improved home hygiene and food preservation'. It is interesting to note that all those much-maligned cleaning products, preservatives and industrial methods of food handling, usually condemned as causing ill-health, are allowing us to eat fresher food in cleaner circumstances. Moreover, treatment for cancer is vastly improved, and there is real optimism that many of the major forms of cancer can be conquered in coming decades.

As for lifestyle, it is certainly true that as long as the number of people who smoke continues to rise in the developing world, rates of lung cancer will rise there too - just at the time when they are falling in the developed world. On the other hand, many of the other campaigns to change lifestyle are misplaced. For example, the evidence that exposure to other people's smoke significantly increases the risk of lung cancer is weak, and the influence of diet on cancer is unclear.

The plain fact is that, smoking apart, the greatest gains in life expectancy will come from better treatment, not how much fresh fruit and veg we eat. It would be better if more attention was paid to cures not sermons.

Growing ageing population drives global cancer rise, Cancer Research UK, 28 April 2005

Worldwide cancer rates 'double', BBC News, 28 April 2005