Women in socioeconomically disadvantaged and less affluent areas of Chicago were less likely to live near a mammography facility with various aspects of care compared with women in less socioeconomically disadvantaged and more affluent areas. This finding could be a contributing factor to the association between disadvantaged areas and late-stage breast cancer diagnosis, according to data presented at the Fifth AACR Conference on The Science of Cancer Health Disparities, held here Oct. 27-30, 2012.
“Other research has found that women living in disadvantaged neighborhoods are more likely to be diagnosed with more biologically aggressive forms of breast cancer,” said Jenna Khan, M.P.H., a doctoral candidate in epidemiology at the University of Illinois at Chicago Division of Epidemiology and Biostatistics. “The disproportionate lack of access to high-quality screening for these women who may actually need it the most is likely to be contributing to racial and socioeconomic disparities in breast cancer stage at diagnosis and survival.”
Khan and colleagues, in collaboration with the Metropolitan Chicago Breast Cancer Task Force, defined an index of social disadvantage from the 2010 census tract data on the percentage of families below the poverty line, families receiving public cash assistance or food stamps, unemployed persons and female-headed households with children.
They created an index of affluence based on the percentage of families with incomes of $100,000 or more, adults with at least a college education and adults with white-collar jobs.
Their data revealed that when compared with tracts considered to be less socially disadvantaged, more socially disadvantaged tracts were less likely to be located near any facility (47 percent versus 66 percent), facilities designated as American College of Radiology-accredited Breast Imaging Centers of Excellence (BICOE; 7 percent versus 36 percent), facilities that offer diagnostic mammography (44 percent versus 52 percent), facilities with at least one breast imaging-dedicated radiologist (31 percent versus 60 percent) and facilities with digital machines (32 percent versus 53 percent).
Similarly, those tracts designated as less affluent were less likely than more affluent tracts to be located near any facility (30 percent versus 77 percent), BICOE-designated facilities (1 percent versus 37 percent), facilities that offer diagnostic mammography (23 percent versus 61 percent), facilities with at least one breast imaging-dedicated radiologist (27 percent versus 71 percent) and facilities with digital machines (16 percent versus 61 percent).
“We recognize that geographic access is only one potential barrier in accessing facilities with quality mammography screening,” Khan said. “Other factors, such as insurance status, beliefs about screening and competing priorities, also affect access and utilization of mammography screening.”
The distribution of mammography facility and census tract characteristics in Chicago
Introduction: Living in neighborhoods with greater socioeconomic disadvantage has been associated with lower use of preventive services and later stage at breast cancer diagnosis. Unequal distribution of quality mammography screening services may contribute to these associations. We compared the distribution of mammography facility characteristics with census tract level measures of social disadvantage and affluence in Chicago.
Methods: An index of social disadvantage was defined from 2010 census tract data on the percentage of: families below the poverty line, families receiving public cash assistance, families receiving food stamps, unemployed persons, and female-headed households with children. An index of affluence was defined from the percentage of: families with incomes of $100,000 or more, adults with a college education or more, and in the civilian labor force in a white collar job. High disadvantage and high affluence were each defined as >1 standard deviation above the mean of the corresponding index. Low disadvantage and low affluence were each defined as >1 standard deviation below the mean of the corresponding index. Mammography facilities participating in the Metropolitan Chicago Breast Cancer Task Force 2010 Mammography Capacity Survey were categorized by American College of Radiology accredited Breast Imaging Center of Excellence (BICOE) designation, whether they offered diagnostic mammography, whether they had at least one breast imaging dedicated radiologist on staff (>75% time spent reading breast images), and whether they used digital vs. analog mammography machines. A one-mile buffer was created around facilities to calculate the percentage of nearby tracts with more or less disadvantage and affluence.
Results: 47 of the 49 mammography facilities located in or within 1 mile of the Chicago city boundary participated in the survey. More socially disadvantaged tracts were less likely than less socially disadvantaged tracts to be located near any facility (47% vs. 66%), BICOE designated facilities (7% vs. 36%), facilities that offer diagnostic mammography (44% vs. 52%, p=0.21), facilities with at least one breast imaging dedicated radiologist (31% vs. 60%) or facilities with digital machines (32% vs. 53%). Likewise, less affluent tracts were less likely than more affluent tracts be located near any facility (30% vs. 77%), BICOE designated facilities (1% vs. 37%), facilities that offer diagnostic mammography (23% vs. 61%), facilities with at least one breast imaging dedicated radiologist (27% vs. 71%) or facilities with digital machines (16% vs. 61%). All p values were < .01 with the exception noted above.
Conclusions: There is an unequal geographic distribution of mammography facilities with higher quality screening characteristics by areas of social disadvantage and affluence in Chicago. This inequity may be a contributing factor to the association between these disadvantaged areas and late stage breast cancer diagnosis.
The study was funded by the Susan G. Komen for the Cure Postbaccalaureate Training in Disparities Research Grant, awarded to the University of Illinois at Chicago.
Jenna Khan1, Jennifer Orsi2, Garth Rauscher1, Anne Marie Murphy2, Danielle Dupuy2. 1University of Illinois at Chicago, Chicago, IL, 2Metropolitan Chicago Breast Cancer Task Force, Chicago, IL.
American Association for Cancer Research