'Cancer will claim 10m lives a year by 2020'

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Cancer is becoming more common despite the huge financial and intellectual resources invested in curbing its growth.

Cancer is becoming more common despite the huge financial and intellectual resources invested in curbing its growth.

Figures published today show that last year there were 10 million new cases around the world, six million deaths and 22 million people living with the disease who had been diagnosed in the previous five years.

The global burden of the disease was up 22 per cent, in incidence and mortality, compared with 1990 and is set to increase by 50 per cent over the next two decades, according to the International Agency for Research on Cancer (IARC) in Lyon, France.

However, countries will be affected in different ways, and cancers that are increasing in incidence in some parts of the world are falling in others. Globally, breast and prostate cancer are increasing but stomach cancer is falling.

Lung cancer, the world's commonest malignant disease, which claimed 1.1 million lives last year and accounted for 12.3 per cent of all new cancer cases, is rising sharply in southern and eastern Europe, but it has passed its peak in northern and western Europe and the United States.

The figures have been collected by Maxwell Parkin of IARC and are published in the monthly journal The Lancet Oncology. It is the first time an attempt has been made to assess the global cancer burden since 1990.

Dr Parkin, an epidemiologist, says most breast cancer is due to lifestyle and environment. Its incidence is high in all developed countries, with the exception of Japan, and low in African and Asian populations – but increasing.

The best evidence for the impact of lifestyle on breast cancer comes from studies showing the striking changes in risk after migration. Italy and Poland have low levels of breast cancer but Poles and Italians who have moved to Australia show high rates, especially if migration took place in childhood. Similarly, Asians who moved to the US show sharp increases in risk between first, second and third generations.

Breast cancer is only a risk for half the population ­ women ­ yet it is the second most common cancer in the world after lung cancer. Because survival prospects are good compared with other cancers, there are 3.9 million women alive who have had the condition diagnosed within the past five years, more than for any other cancer. However, the disease still claims 370,000 lives a year, accounting for 13.9 per cent of cancer deaths among women.

Trends in lung cancer are linked to the maturity of the smoking epidemic and reflect levels of smoking 30 years ago. Cigarette smoking was taken up earlier in western Europe and the US than in eastern Europe. It is now rising quickly in the developing world, heralding future devastation.

Prostate cancer is more than three times more common in the developed than the developing world but this mostly reflects better detection and screening. However, as with breast cancer, migrants from low-risk countries such as Japan to high-risk countries such as the US show large increases in incidence.

Stomach cancer is linked with infection by the bacterium Helicobacter pylori, which affects 80 to 90 per cent of the population in the developing world but only 50 per cent in the developed. The cancer is falling possibly because of reduced transmission of the infection in childhood through improved hygiene and less overcrowding, as well as better diet.

By 2020, 15 million new cases of cancer and 10 million deaths are expected each year. This will occur even if current trends remain unchanged, because of the growth in the world's population and ageing.