The global death toll from cancer rose to 8.2 million in 2012 with sharp rises in breast cancer as the disease tightened its grip in developing nations struggling to treat an illness driven by Western lifestyles.
Cancer deaths were up 8 percent from 7.6 million in a previous survey in 2008 and breast cancer killed 522,000 women last year, up 14 percent in the same period, according to the World Health Organization's International Agency for Research on Cancer (IARC).
"Breast cancer is also a leading cause of cancer death in the less developed countries of the world," said David Forman, head of IARC's Section of Cancer Information, the group that compiles the global cancer data.
He said this was "partly because a shift in lifestyles is causing an increase in incidence, and partly because clinical advances to combat the disease are not reaching women living in these regions."
An estimated 14.1 million people developed cancer in 2012, up from 12.7 million in 2008. And 1.7 million women were newly diagnosed with breast cancer last year, up by more than 20 percent from 2008.
IARC's report, called GLOBOCAN 2012, gives the most up-to-date estimates for 28 different types of cancer in 184 countries and offers an overview of the global cancer burden.
It found that the most commonly diagnosed cancers worldwide in men and women combined were lung, breast and colorectal cancers. The most common causes of cancer death were lung, liver and stomach cancers.
Projecting forward, IARC experts said they expected "a substantive increase" in cancer cases worldwide, with annual new cases predicted to rise to 19.3 million by 2025 as the global population both grows and ages.
Worldwide trends show that in developing countries going through rapid societal and economic change, the shift towards lifestyles more typical of richer industrialized countries leads to a rising burden of cancers linked to reproduction, diet and hormones.
The IARC report said cancer incidence - the number of new cases each year - has been increasing in most regions of the world, but noted what it said were "huge inequalities" between rich and poor countries.
While rates of new cancer cases are still highest in more developed regions, death rates are relatively much higher in less developed countries because people's tumors are often not detected and diagnosed early enough due to a lack of screening and access to treatment.
"An urgent need in cancer control today is to develop effective and affordable approaches to the early detection, diagnosis, and treatment of breast cancer among women living in less developed countries," said Christopher Wild, IARC's director.
He said it was critical to bring rates of disease and death in poorer countries in line with progress made in recent years in treating and curing some cancers on wealthier countries.
One stark example of the inequality is in cervical cancer - which kills hundreds of thousands of women in Africa each year but can be largely avoided with a vaccine or successfully treated if it is picked up early enough with screening.
In sub-Saharan Africa, 34.8 new cases of cervical cancer are diagnosed per 100,000 women each year, and 22.5 per 100,000 women die from the disease. That compares with 6.6 and 2.5 per 100,000 women respectively in North America.
"These findings bring into sharp focus the need to implement the tools already available for cervical cancer, notably HPV vaccination combined with well organized national programs for screening and treatment," Wild said.