LONDON - For years, it was assumed that young women in poor countries had a higher risk of dying in childbirth than from cancer. But a new study shows that's changing -- experts say breast and cervical cancers are killing more women than labour in more than 60 developing countries.

In the first global review of breast and cervical cancer, researchers estimated that the number of new breast cancer cases rose from about 641,000 cases in 1980 to 1.6 million cases last year.

Researchers at the Institute for Health Metrics and Evaluation at the University of Washington analyzed cancer registries and other data from 187 countries, but also used modelling techniques to calculate their cancer rates.

In contrast, the World Health Organization says there were about 900,000 breast cancer cases in 2008.

Experts in the new study found that cervical cancer rose from 378,000 new cases in 1980 to about 454,000 cases in 2010, with most of those cases in the developing world. Still, the death rate has been dropping as more countries introduce regular screening.

Officials estimate that about 343,000 women die in childbirth every year, most in the developing world. In comparison, breast cancer kills 425,000 women a year, while cervical cancer kills about 200,000.

The increase in breast cancer is partly explained by aging populations, since older women are more vulnerable. But the globalization of bad habits -- people eating more fatty foods and exercising less -- is also driving the growth, particularly in Asia and Latin America.

"People may wonder what the urgency is in addressing these cancers, but the numbers are staggering," said Jan Coebergh, a cancer expert at Erasmus University Medical Centre in Rotterdam, the Netherlands, who wrote an accompanying commentary to the study. "It's like six jumbo jets crashing every day."

The study was paid for by the breast cancer group Susan G. Komen for the Cure and the Bill & Melinda Gates Foundation. It was published online Thursday in the medical journal The Lancet.

"We've been getting better at helping women with breast cancer survive in the West," said Christopher Murray, one of the paper's authors. "Now we need to make that a priority for women everywhere."