Breast and cervical cancer cases still rising
MedWire News: The incidence and mortality rates of breast and cervical cancer are rising in most countries worldwide, especially in women of reproductive age from developing countries, show data published in The Lancet.
Christopher Murray and colleagues, from the University of Washington in Seattle, USA, report that global breast cancer incidence more than doubled between 1980 and 2010, increasing from 641,000 cases to 1.6 million cases at an annual rate of increase of 3.1%.
During the same period, deaths from breast cancer rose from 250,000 in 1980 to 425,000 in 2010 - an annual rate of increase of 1.8%. Approximately one in six of the deaths that occurred in 2010 were among women of reproductive age (15-49 years) from developing countries.
For cervical cancer, incidence rose from 378,000 cases in 1980 to 454,000 in 2010 (0.6% increase per year), while deaths increased from 174,000 to 200,000 over the same period (0.5% increase per year). As with breast cancer, cervical cancer mortality rates were particularly high among reproductive age women from developing countries. These women accounted for approximately one in four of all deaths in this age group in 2010.
The findings are the result of a study that reviewed population-based cancer registries, vital registration data, and verbal autopsy data for the period 1980-2010 and then used that data to develop annual age-specific assessments of breast and cervical cancer in 187 countries.
The researchers note that trends in breast cancer incidence and mortality varied considerably across regions and countries.
In 1980, 65% of all breast cancer cases were in developed countries. By 2010, the proportion of breast cancer cases in the developed world had halved, with the majority of cases (approximately 70%) found in developing countries. Indeed, some developing countries saw a rise in breast cancer cases of more than 7.5% annually, more than twice the global rate.
The risk for cervical cancer was much higher in developing countries throughout the study. Overall, 76% of new cervical cancer cases occurred in developing regions. Sub-Saharan Africa alone made up 22% of all cervical cancer cases, or more than 76,000 cases in 2010.
"On the basis of trends recorded in this study, breast and cervical cancer are likely to soon approach maternal causes as a crucial cause of mortality in women of reproductive age in developing countries," observe Murray et al.
"Indeed, if the trends of the past 3 decades were to continue during the next 15 years, the ratio of maternal deaths to breast and cervical cancer deaths in developing countries in the reproductive age group will decrease from 2.3 to 1.3," they add.
The team therefore calls for policy makers to pay more attention to strengthening established health-system responses to reduce breast and cervical cancer, especially in developing countries.
"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 Murray. "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."
By Laura Dean