Worldwide cancer rates are set to double by 2020, a report published this week by the World Health Organization says.
Currently 10 million new cancers are diagnosed each year worldwide, but unless there is an effective prevention campaign, the number will rise to 20 million in 17 years' time, says the report. If preventive measures were adopted, that figure could be reduced by a quarter, it states.
“Cancer is emerging as a major problem globally, both in more developed and in less developed countries,” says the report. “Political will and international collaboration are now required for effective cancer control.”
Current levels of smoking and unhealthy lifestyles are the main causes. The increasing proportion of elderly people will also contribute to the rise in the number of cancer cases worldwide.
The report looks at the causes of cancer, treatments, and prevention measures.
Cancer mortality in the world as a whole is more than twice that in developing countries, a factor the report attributes to the earlier onset of the tobacco epidemic, earlier exposure to occupational carcinogens, and the Western diet and lifestyle.
In developing countries, up to a quarter of cancers are caused by infections, including hepatitis B, which is linked to liver cancer, and the human papillomavirus, which is linked to cancer of the cervix. Between 1985 and 1997, the number of deaths in developing countries increased by at least 62% for circulatory diseases and cancers.
In her foreword to the report, Dr Gro Harlem Brundtland, the director general of WHO, says that tobacco consumption remains the most important avoidable cancer risk. “During the twentieth century approximately 100 million people died worldwide from tobacco-associated diseases. Half of all regular smokers are killed by the habit and one quarter die prematurely before the age of 70,” she wrote.
WHO is particularly concerned about the rising incidence of cancer in developing countries and the disproportionate suffering caused in disadvantaged populations.
It is soon to adopt the Framework Convention on Tobacco Control, which aims to reduce morbidity and mortality associated with tobacco consumption. It has also endorsed a global strategy giving the highest priority to cancer control measures.
The report calls for measures promoting a healthy diet, smoking cessation, and better access to immunisation. 
Footnotes
World Cancer Report is available from bookshops or direct from bookorders@who.ch