Dr. Peter Boyle said the reasons for the increase include population growth, longer life expectancy, more people smoking in the developing world and a lack of health care in poor countries.

In 2000, the agency estimated 11 million new cases of diagnosed cancer worldwide, seven million deaths from cancer and 25 million people living with cancer.

"We currently estimate that between the year 2000 and 2030, there'll be a more than doubling of the numbers of cases of cancer diagnosed each year," Boyle said. "And the great majority of this increase is going to be in the low- and medium-resource countries."

The agency, part of the World Health Organization, expects that by the year 2030, there will be 27 million cases of cancer, 17 million deaths from cancer and 75 million people living with cancer.

"We've been concentrating on cancer in high-resource countries and until essentially AIDS came along, we haven't looked too closely at what's going on in low-resource countries," Boyle told a news conference.

But he said new research shows that as time has progressed, there has been an increasing shift of cancer to poor countries.

"What's going to happen between now and 2030 is that the population is going to increase from about 6.5 billion to 8 billion in 2030," Boyle said. "So even if the risks remain constant at each five-year age group, because we've got more people around, we're going to have more cases of cancer."

An increase in life expectancy in the majority of countries, with the exception of some AIDS-ravaged countries in Africa, also is leading to a rise in cancer cases, he said.

Both China and India have continual growth in the number of people reaching older ages, Boyle said. "So if you've got more old people in the population with the same risks as the younger people, you're going to have more cases of cancer in the older population," he said.

Boyle said one of the unfortunate successes for developed countries in the last 40 years has been their export of cancer risk factors, such as cigarette smoking and alcohol consumption, to poor countries.

"These three elements are going to come together and that is going to drive up the global cancer button over the next 30 years," Boyle said.