For seven years, South Dakota had breast cancer incidence rates below or at the national average until 2011, when the rate shot up from well below the national rate to well above. By 2012, the Rushmore state had the highest rate in the country, according to data presented by the South Dakota Health Department May 19 at the South Dakota Demography Conference in Sioux Falls.
"Our rates began to increase starting in 2011 to where we have the highest rate in country. We don't know why," state epidemiologist Lon Kightlinger told conference attendees.
In 2012, South Dakota had 141.4 female breast cancer cases per 100,000 in population, according to the federal Centers for Disease Control. That's ahead of No. 2 Hawaii (139.8) and No. 3 Washington (137.2). Neighboring Wyoming tied with Arizona for the lowest incidence in 2012, 107.2 per 100,000 population.
In 2012, South Dakota had 672 total female breast cancer cases, up from 629 in 2011 and 530 in 2010. The number climbed again in 2013 to 715 total cases, for an incidence rate of 146 per 100,000 in population.
At the same time, South Dakota's breast cancer death rate in 2012 remained low, according to the CDC. With 19.1 deaths per 100,000 population, South Dakota was among the third of states with the lowest rates, although the state had the highest rate in that group.
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