Why breast cancer deaths are down 42 percent in the U.S.

Some promising news for people diagnosed with breast cancer in the United States: The number of lives claimed by the condition has dropped by 42 percent since 1989. However, some outside North America aren’t faring as well, with increases in the mortality rate reported in South Korea and various locations across Latin America.

Overall, the study, conducted by the International Prevention Research Institute in Lyon, France, indicated that deaths resulting from breast cancer declined in 39 out of 47 countries, including in the United States and most of Europe, thanks to advances in detection and treatment.

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Latin America had mixed results. The number of deaths from breast cancer decreased in Argentina and Chile, but increased in Brazil and Columbia. The most dramatic change was in South Korea, with an overall 83 percent increase in breast cancer mortality.

“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,” Cécile Pizot, the study’s lead author said. “Such quick changes might explain the considerable shift in cancer mortality.”

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So why is there such a stark difference based on location? Pizot thinks it might have to do with the differences in health care systems and patient management, but said that currently there is “little data comparing the management of breast cancer patients across countries.”

There was not, however, a clear connection between the availability of breast cancer screening in mortality trends, with Pizot noting that several countries with similar geographic locations and socioeconomic statuses experienced similar trends — regardless of whether they started widespread mammograms in the 1980s or 2005.

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Pizot also explained that it is difficult to isolate a single common factor that would have such a big impact on the survival rate, but suggested that “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.”