Temporal trends in geographic disparities in small-area breast cancer incidence and mortality, 1988 to 2005.

BACKGROUND: A goal of Healthy People 2010 was to reduce health disparities. We determined the extent of reductions in geographic disparities in five breast cancer screening indicators.
METHODS: We examined the extent of reductions in geographic disparities in five breast cancer screening indicators using data about women ages 40 years and older from 200 counties in the 1988 to 2005 Surveillance, Epidemiology, and End Results Program database. County-level trends in five breast cancer indicators (in situ, stage I, lymph node-positive, locally advanced, and mortality) were summarized using the estimated annual percentage change. Observed county rates were smoothed using hierarchical Bayesian spatiotemporal methods to calculate measures of absolute and relative geographic disparity and their changes over time.
RESULTS: For in situ breast cancer, absolute disparity increased 93.7% during 1988 to 2005. Relative disparity declined 61.5% during the entire study period. Absolute and relative disparity for stage I breast cancer declined 18.5% and 41.4%, respectively. Absolute disparity for lymph node-positive breast cancer declined 37.9% during the study period, whereas relative disparity declined 17.6%. Absolute disparity for locally advanced breast cancer declined 66.5%, whereas relative disparity declined 17.8% during the study period. Absolute disparity in breast cancer mortality declined 60.5%, whereas relative disparity declined 19.8%.
CONCLUSIONS: Absolute and relative geographic disparities narrowed over time for all breast cancer indicators except for in situ breast cancer. IMPACT: Progress has been made toward reducing geographic disparities in breast cancer outcomes, particularly in advanced-stage breast cancer incidence and mortality rates, although disparities remain.