Advanced Stage Breast Cancer Among Women 40 Years and Older, by Medical Service Study Area (MSSA), California Counties, 2010-2014

Data from the statewide, population-based, California Cancer Registry (CCR) were analyzed to identify geographic areas with a comparatively high proportion of breast cancers diagnosed at late, or otherwise, advanced stage.  Data on women from the CCR aged 40 years and older diagnosed with breast cancer between January 1, 2010 and December 31, 2014 was used.  Proportional incidence ratios (PIRs) were calculated by determining the proportion of late-stage breast cancer in counties and Medical Service Study Areas (MSSAs) relative to the proportion in upper-socioeconomic, non-Hispanic white women statewide.  The outcomes were mapped, providing visual representations of areas with an excess of advanced stage breast cancer.