Cancer will surpass heart disease as the world's number one killer by 2010, with poorer countries set to suffer most from the trend due to smoking, high-fat diets and other factors, according to international health officials.

Some 12 million new cancer cases will be diagnosed this year and more than seven million people will die from the disease, the World Health Organisation (WHO) reported.

A projected 38 percent population increase in less developed countries between 2008 and 2030 was identified among several demographic changes underlying these trends.

The report estimates that between 20 and 26 million new cancer diagnoses will be made in 2030, with between 13 and 17 million cancer-related deaths.