More women dying from breast and cervical cancer at a younger age in developing countries
The number of cases and deaths from breast and cervical cancer are rising in most countries, especially in the developing world where more women are dying at younger ages, according to a new global analysis by the Institute for Health Metrics and Evaluation (IHME) at the University of Washington.
Breast cancer cases more than doubled around the world in just three decades, from 641,000 cases in 1980 to 1.6 million cases in 2010, a pace that far exceeds global population growth. During that same period, deaths from breast cancer rose from 250,000 to 425,000 in 2010. This much slower increase than the rise in cases indicates that screening and treatment programs are having an impact. Cervical cancer cases grew from 378,000 cases in 1980 to 454,000 in 2010. Cervical cancer deaths grew to 200,000 over the same period, nearly the same pace as cases.
The new study, "Breast and cervical cancer trends for 187 countries, 1980-2010: a systematic analysis," is published in The Lancet.
"Women in high-income countries like the United States and the United Kingdom are benefiting from early cancer screenings, drug therapies, and vaccines," said Dr. Rafael Lozano, Professor of Global Health at IHME and one of the paper's co-authors, "We are seeing the burden of breast and cervical cancer shifting to low-income countries in Africa and Asia. This is one of the early signs of the emerging threat of noncommunicable diseases in these countries. Everyone has been talking about that threat. Now the trend is clear."
Coinciding with the study's release, IHME is publishing a report, The Challenge Ahead: Progress and setbacks in breast and cervical cancer, which provides global, regional, and country data for cases, deaths, and risks over the past three decades. The work was funded by Susan G. Komen for the Cure®.
"We at Susan G. Komen for the Cure have seen firsthand the growing burden of breast and cervical cancers in our outreach to low-resource countries in Africa, the Middle East, Latin America, and central Europe. This report confirms what we have witnessed, and adds urgency to calls to world health leaders to make cancer screening, treatment, and education a priority in the developing world," said Elizabeth Thompson, president of Susan G. Komen for the Cure®.
Komen on Sept. 13 announced a global partnership with the George W. Bush Institute, the U.S. State Department, and UNAIDS to support breast and cervical cancer screening in Africa and Latin America.
In 1980, 65% of all breast cancer cases were in developed countries. By 2010, the share of breast cancer cases in the developed world shrank to less than half, with the majority of cases now found in developing countries. Some developing countries saw a rise in breast cancer cases of more than 7.5% annually, more than twice the global rate.
The risk of cervical cancer is much higher in developing countries. Overall, 76% of new cervical cancer cases occur in developing regions. Sub-Saharan Africa alone makes up 22% of all cervical cancer cases, or more than 76,000 in 2010."If more women are developing breast and cervical cancer during their reproductive years, this adds more pressure on families and societies already suffering from high rates of infectious disease and child mortality," said Dr. Mohammad Forouzanfar, the paper's lead author and an IHME Post-Graduate Fellow.
In the past, complications from pregnancy and childbirth were among the leading causes of death in women under age 50. Based on current trends, breast and cervical cancer are likely to soon approach maternal causes of death in developing countries. In the Middle East and North Africa, for example, nearly 40% of all breast cancer deaths are in women of reproductive age, compared to 10% in much of Europe. In countries such as Bangladesh, the fraction is higher than 50%.
"We have poured an enormous amount of resources into addressing the serious concern of maternal mortality worldwide, and we've seen a great deal of progress," said Alan Lopez, Head of the University of Queensland School of Population Health and one of the report's co-authors. "To expand that commitment, breast and cervical cancer need to become a standard part of the efforts aimed at saving more mothers' lives."
The authors hope researchers and policymakers will be able to build on these findings and pinpoint some of the reasons for stark differences between countries. In countries such as the US, 1 in 32 women risked dying from breast cancer in 1980, and that risk decreased to 1 in 47 by 2010. In countries such as Rwanda, the opposite happened: 1 in 97 women risked dying from breast cancer in 1980, and now 1 in 60 women are at risk.
Even within regions, the trends can be very different. Women in Peru have half the risk today of dying from breast cancer that they did in 1980, while the risk has remained nearly the same over 30 years in nearby Argentina, where 1 in 34 women are at risk of dying. In China, women had a 1 in 133 risk of dying from cervical cancer in 1980 and now have a risk of 1 in 342, one of the lowest in the world. Over the same period, the risk of dying from cervical cancer for women living in Thailand stayed at about 1 in 100.
"The fact that similar countries with similar populations have very different trends tells us that all the usual suspects, such as diet and obesity, are only part of the picture," said Dr. Christopher Murray, IHME Director and one of the paper's co-authors. "This is why it is critical to build the evidence base in this area, by gathering data through expanded cancer registries and use of new techniques, such as verbal autopsies. Then we will be able to answer why the progress we are seeing in some countries is not shared elsewhere."