WASHINGTON - 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, international health experts warned on Tuesday.

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

A projected 38 per cent 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.

'The rapid increase in the global cancer burden represents a real challenge for health systems worldwide,' Mr Peter Boyle, director of the WHO's International Agency for Research on Cancer, said in a statement introducing the report.

Population growth and the spread of the disease present challenges to cancer care, especially in Africa, the report found.

The global cancer burden is also rising because of western lifestyle behaviours being adopted in developing countries, primarily smoking, high-fat diets and less physical activity.

Leading global cancer organisations met on Tuesday in Atlanta where they called on governments to act, pressing for immediate ratification of an international tobacco control treaty and asking the US to comprehensively regulate tobacco use and invest in cancer vaccines and research.

'Even in a challenging economy, people realize that with cancer there is progress to be made and prevention measures to be taken,' said Lance Armstrong, the world cycling champion who has helped spearhead the fight against the disease after he survived testicular cancer.

The Atlanta event was intended to bring more attention to the threat of cancer worldwide, which some developing nations do not recognise as an urgent health problem.

'It is my hope that by bringing proven interventions to places in the world impacted most by this disease, we can diminish needless suffering and save many lives,' said Mr John Seffrin of the American Cancer Society.

The organisation announced it would launch a service to help tobacco users quit smoking in India.

Mr Hala Moddelmog, president and CEO of the breast cancer foundation Susan G.

Komen Race for the Cure, pushed for a 'global health diplomacy' approach by taking lessons learned in the United States to developing countries.

Lung cancer was found to have the highest rates of incidence and mortality in the world. Cervical cancer is a leading cause of cancer deaths in women in poorer nations, where breast cancer incidence rates have increased by up to five per cent per year.

The report said the troubling trends could be reduced by increasing awareness, developing cancer prevention and acquiring more cancer data. -- AFP