Breast cancer stage, surgery, and survival statistics for Idaho's National Breast and Cervical Cancer Early Detection Program population, 2004-2012.

introductionThe National Breast and Cervical Cancer Early Detection Program (NBCCEDP) provides access to breast and cervical cancer screening for low-income, uninsured, and underinsured women in all states and US territories. In Idaho, a rural state with very low breast and cervical cancer screening rates, this program is called Women's Health Check (WHC). The program has been operating continuously since 1997 and served 4,719 enrollees in 2013. The objective of this study was to assess whether disparities existed in cause-specific survival (a net survival measure representing survival of a specified cause of death in the absence of other causes of death) between women screened by WHC and outside WHC and to determine how type of surgery or survival varies with stage at diagnosis.

methodsWHC data were linked to Idaho's central cancer registry to compare stage distribution, type of surgery, and cause-specific survival between women with WHC-linked breast cancer and a comparison group of women whose records did not link to the WHC database (nonlinked breast cancer).

resultsWHC-linked breast cancer was significantly more likely to be diagnosed at a later stage of disease than nonlinked breast cancer. Because of differences in stage distribution between WHC-linked and nonlinked breast cancers, overall age-standardized, cause-specific breast cancer survival proportions diverged over time, with a 5.1 percentage-point deficit in survival among WHC-linked cases at 5 years of follow-up (83.9% vs 89.0%). Differences in type of surgery and cause-specific survival were attenuated when controlling for stage.

conclusionThis study suggests that disparities may exist for Idaho WHC enrollees in the timely diagnosis of breast cancer. To our knowledge, this is the first study to publish comparisons of cause-specific breast cancer survival between NBCCEDP-linked and nonlinked cases.