Mortality from Breast Cancer Is Lower Worldwide, but Disparities Remain
While the breast cancer mortality rate in many nations has declined, this is not true of South Korea and Latin America.
Cécile Pizot, MSc
Although many nations have seen a decline in mortality rates from breast cancer, disparities persist, specifically in South Korea and some Latin American nations, according to findings of a recent study analyzing trends in 47 countries over approximately the last quarter century.
Using information from the World Health Organization database, researchers found that breast cancer mortality declined in 39 of the countries, including the United States and the most developed European nations. Of the latter, England and Wales reported the most significant decline, with a reduction in breast cancer—related mortality of 46%. The findings were shared by the study’s lead author, Cécile Pizot, MSc, at the 2016 San Antonio Breast Cancer Symposium.
“Comparing mortality trends between countries helps identify which healthcare systems have been the most efficient at reducing breast cancer mortality,” explained Pizot, of the International Prevention Research Institute in Lyon, France, in a statement.
South Korea saw the most dramatic increase of breast cancer mortality, with an 83% increase overall and higher mortality in every age group. Despite the increase, the breast cancer mortality rate of South Korea (5.3 per 100,000 women) remains lower than that of the United States (14 per 100,000 women) during the 2011-2013 period.
Latin American nations experienced scattered increases in mortality; for example, Brazil and Colombia saw mortality rates increase in women of all age groups, while in Argentina and Chile mortality rates decreased in all women.
Pizot suggested that the increase in South Korea could be a result of major changes in the society since the 1950s, as the country “quickly evolved from an agricultural, developing country to a highly industrialized and Westernized country.”
Breast cancer mortality rates in the United States declined 42%, from 22 deaths per 100,000 women, in 1987-1989, to 14 deaths per 100,000 women, in 2011-2013, the researchers reported. The rate declined for women in all age groups: 50% for women aged <50 years, 44% for women aged 50-69 years, and 31% for women aged ≥70 years.
Additionally, the study identified a trend globally indicating that breast cancer mortality rates declined more for women aged <50 years than for women aged >50. Pizot attributed this to the fact that younger women often received more intense treatments (such as longer courses of chemotherapy), prolonging their survival.
It is difficult to determine the effect of breast cancer screening from mortality trends data, Pizot acknowledged. The study found that several nations with similar geographic locations and socioeconomic status experienced similar trends, irrespective of whether the country has used mammography screening since the 1980s or the screening was introduced in 2005 or later. “This finding underlines the difficulty of isolating a single, common factor that would have a major influence on mortality trends,” Pizot said.
She added that future research should focus on other areas of breast cancer management, such as risk factors, drug therapies, access to care, and multidisciplinary teams.
“Differences in healthcare systems and patient management could explain discrepancies in mortality reduction between similar countries,” Pizot said. “However, there are at present little data comparing the management of breast cancer patients across countries.”
Limitations of the study included a lack of data available for many Latin American, Asian and African countries.
Pizot C, Boniol M, Boyle P, et al. Overview of breast cancer mortality trends in the world. Presented at: 2016 San Antonio Breast Cancer Symposium; December 6-10, 2016; San Antonio, TX. Abstract P5-08-04.