A third of cancers are preventable, says WHO

Cancer rates could increase by 50 per cent to 15 million by 2020, according to new figures released by the World Health Organisation this week. The 'World Cancer Report' also suggests that healthy lifestyles and government initiatives could stem this trend, and prevent as many as one third of cancers worldwide.

A healthy diet and frequent consumption of fruit and vegetables is identified as one of three prime areas, (along with reducing tobacco consumption andearly detection through screening) where action is needed to cut the growing cancer rates.

"Governments, physicians, and health educators at all levels could do much more to help people change their behaviour to avoid preventable cancers,"​ said Dr Bernard W. Stewart, co-editor of the report, director of Cancer Services, and professor at the Faculty of Medicine, University of New South Wales, Australia. "If the knowledge, technology and control strategies outlined in the World Cancer Report were applied globally, we would make major advances in preventing and treating cancers over the next twenty years and beyond."​

"From a global perspective, there is strong justification for focusing cancer prevention activities particularly on two main cancer-causing factors - tobacco and diet,"​ added Dr Rafael Bengoa, director of the Management of Non-communicable disease at WHO.

The report referred to recent studies showing that consumption of fruit and vegetables may reduce the risk of cancers of the pharynx, larynx, lung, oesophagus, stomach, colon and cervix. Recent data from the European Prospective Investigation into Cancer and Nutrition (EPIC), suggests that a daily consumption of 500g of fruits and vegetables can decrease incidence of cancers of the digestive tract by up to 25 per cent.

The report also suggested that consumption of locally produced vegetables, fruit and agricultural products should be encouraged among the developing world, to avoid the adoption of Western style dietary habits. IARC says that such actions would have health benefits beyond cancer, since other common non-communicable diseases, notably cardiovascular disease and diabetes, share the same lifestyle-related risk factors.

There was also some good news however - stomach cancer, among the most common malignancies worldwide, with the highest incidence in Eastern Asia, the Andean regions of South America and Eastern Europe, is declining world-wide, in some regions almost dramatically. The drop in incidence and mortality rates is particularly impressive in Nordic countries in which fish consumption is traditionally high, for example Iceland.

In populations that still prefer salty food, stomach cancer rates remain high but have also started to decline significantly, thought to be the result of better availability in many countries of fresh fruit and vegetables throughout the year.

Colon and rectum cancers, caused by a diet rich in fat, refined carbohydrates and animal protein, can also be reduced by increasing fruit and vegetable consumption suggest studies.

"By acting now, by the year 2020, countries can achieve significant reductions in cancer rates and in mortality from cancer,"​ said Dr Stewart. "These opportunities exist, and the only question is whether we will take advantage of them for the benefit of all humankind."​

As part of its effort to reduce chronic disease the WHO is currently preparing its Global Strategy on Diet, Physical Activity and Health, under a May 2002 mandate from Member States to address the growing global burden of chronic diseases, including cancers, cardiovascular diseases, diabetes and obesity.

The strategy is being developed through consultation with Member States, other UN agencies, the private sector and civil society and will be presented to the World Health Assembly in May 2004. It seeks to offer governments advice on nutrition and physical activity goals and population-based interventions to reduce the prevalence of chronic disease including cancer.