Breast cancer mortality rates continue to fall around the world, but there are disparities, particularly in South Korea and Latin America, according to a study presented this week at the San Antonio Breast Cancer Symposium (SABCS).
Breast cancer represents a quarter of all cancers in women worldwide, and comparing mortality trends between countries can help identify which nations are providing the most effective care, lead author Cécile Pizot of the International Prevention Research Institute in Lyon, France, said in a statement released by SABCS.
"Differences in healthcare systems and patient management could explain discrepancies in mortality reduction between similar countries," she said.
Pizot and colleagues used data from the World Health Organization (WHO) database on breast cancer deaths to calculate mortality rates from 1987 to 2013. They then stratified the results according to age.
Breast cancer mortality fell in 39 out of 47 countries, including the U.S. and most European nations -- with England and Wales showing the sharpest drop of 46%, the group found. Results were mixed in Latin America: For example, Brazil and Colombia showed mortality rate increases in women of all age groups, but Argentina and Chile showed declines in the mortality rate across all women.
South Korea had the greatest increase in breast cancer mortality, with an 83% rise overall and higher mortality in every age group. However, South Korea's breast cancer mortality rate is still lower than that of the U.S., at 5.3 deaths per 100,000 women in South Korea, compared with 14 deaths per 100,000 women in the U.S. between 2011 and 2013.
"South Korea has experienced major societal changes since the 1950s and quickly evolved from an agricultural, developing country to a highly industrialized and Westernized country," Pizot said. "Such quick changes might explain the considerable shift in cancer mortality."
Other results are as follows:
- The breast cancer mortality rate in the U.S. fell 42% over the time period and declined in each age group: by 50% in women younger than 50, by 44% in women between 50 and 69, and by 31% in women 70 or older.
- Globally, breast cancer mortality rates declined more for women younger than 50 than for women older than 50.
- Breast cancer screening's role is not clear in mortality trends. Countries with similar geographic locations and socioeconomic status experienced similar trends, no matter whether mammography screening had been in place since the 1980s or whether it was introduced in 2005 or later.
The study results point to the difficulty of identifying a single, common factor that strongly influences breast cancer mortality trends, Pizot said. Future research on breast cancer mortality should focus on other facets of breast cancer management, including risk factors, drug therapies, access to care, and the use of multidisciplinary teams, she concluded.
