Two reports have warned of an explosion in cancer deaths among women, with a toll, mainly from breast cancer, of some 5.5 million per year by 2030, or roughly the entire population of Denmark.
This represents a near 60-per cent increase in less than two decades, said an analysis conducted by the American Cancer Society (ACS), released Tuesday at the World Cancer Congress in Paris.
As the global population grows and ages, the highest toll will be among women in poor and middle-income countries, it said, and much of it from cancers which are largely preventable.
"Most of the deaths occur in young- and middle-aged adults," placing a heavy burden on families and national economies, said Sally Cowal, senior vice president of global health at the ACS, which compiled the report with pharmaceutical company Merck.
A second report, published in The Lancet medical journal on Wednesday, said the number of women diagnosed with breast cancer alone could almost double to 3.2 million a year by 2030 from 1.7 million in 2015.
For cervical cancer, the number of diagnoses could "rise by at least 25 per cent to over 700,000 by 2030," mainly in low- and middle-income countries, said a statement from The Lancet .
Cancer is already killing one in seven women around the world, said the ACS report - the second highest cause of death after cardiovascular disease.
All four of the deadliest cancers - breast, colorectal, lung and cervical cancer - are mostly preventable or can be detected early, when treatment is more successful.
In poorer countries, a much smaller proportion of cancer cases are diagnosed and treated than in rich ones, while a much bigger group dies.
The relative burden is growing for developing countries as people live longer due to better basic healthcare.
Women in these countries are also increasingly exposed to known cancer risk factors "associated with rapid economic transition," said Cowal, "such as physical inactivity, unhealthy diet, obesity, and reproductive factors" such as postponing motherhood.
"Due to these changes, cancers that were once common only in high-income countries are becoming more prevalent," said the report entitled "The Global Burden of Cancer in Women."
Developing countries hard hit
According to the International Agency for Research on Cancer, there were 6.7 million new cancer cases and 3.5 million deaths among women worldwide in 2012.
Of these, 56 per cent of cases and 64 per cent of deaths were in less developed countries.
"These numbers are expected to increase to 9.9 million cases and 5.5 million deaths among females annually by 2030 as a result of the growth and ageing of the population," said the ACS report.
The biggest concentration is in eastern Asia, with 1.7 million cases and a million deaths in 2012, mainly in China.
The highest ratio of cancer cases per population group are still reported in high-income countries in Europe, the Americas and Asia, but this was partly due to better access to screening and detection.
Deaths, however, were proportionally much higher in low- and middle-income countries with reduced access to diagnosis and treatment. The countries with the highest death rate were Zimbabwe, Malawi, Kenya, Mongolia and Papua New Guinea.
Breast and lung cancer are the two most common types in both rich and poor nations, with colorectal cancer the number three killer in developed countries and cervical cancer in less developed ones.
Cervical cancer can be staved off by vaccination against the cancer-causing Human papillomavirus (HPV) and can be easily detected through regular Papanicolaou (pap) test screens.
The Lancet report, comprised three research papers, said a basic cancer control package could be introduced in low- and middle-income countries for as little as $1.72 per person - the equivalent of just three per cent of current health spending in these countries.
Universal HPV vaccination of all 12-year-old girls could prevent 420,000 deaths worldwide over their lifetime.
"The global community cannot continue to ignore the problem -- hundreds of thousands of women are dying unnecessarily every year," said Richard Sullivan of King's College London, who co-authored The Lancet report.
"Not only are the costs of essential cancer services for women lower than expected, but scale-up of diagnostic, surgical and treatment services are a highly effective investment compared the devastating economic cost to countries, communities and families."