Does Utilization of Screening Mammography Explain Racial and Ethnic Differences in Breast Cancer?

University of California, San Francisco, San Francisco, California, United States
Annals of internal medicine (Impact Factor: 17.81). 05/2006; 144(8):541-53.
Source: PubMed


Reasons for persistent differences in breast cancer mortality rates among various racial and ethnic groups have been difficult to ascertain.
To determine reasons for disparities in breast cancer outcomes across racial and ethnic groups.
Prospective cohort.
The authors pooled data from 7 mammography registries that participate in the National Cancer Institute-funded Breast Cancer Surveillance Consortium. Cancer diagnoses were ascertained through linkage with pathology databases; Surveillance, Epidemiology, and End Results programs; and state tumor registries.
1,010,515 women 40 years of age and older who had at least 1 mammogram between 1996 and 2002; 17,558 of these women had diagnosed breast cancer.
Patterns of mammography and the probability of inadequate mammography screening were examined. The authors evaluated whether overall and advanced cancer rates were similar across racial and ethnic groups and whether these rates were affected by the use of mammography.
African-American, Hispanic, Asian, and Native American women were more likely than white women to have received inadequate mammographic screening (relative risk, 1.2 [95% CI, 1.2 to 1.2], 1.3 [CI, 1.2 to 1.3], 1.4 [CI, 1.3 to 1.4], and 1.2 [CI, 1.1 to 1.2] respectively). African-American women were more likely than white, Asian, and Native American women to have large, advanced-stage, high-grade, and lymph node-positive tumors of the breast. The observed differences in advanced cancer rates between African American and white women were attenuated or eliminated after the cohort was stratified by screening history. Among women who were previously screened at intervals of 4 to 41 months, African-American women were no more likely to have large, advanced-stage tumors or lymph node involvement than white women with the same screening history. African-American women had higher rates of high-grade tumors than white women regardless of screening history. The lower rates of advanced cancer among Asian and Native American women persisted when the cohort was stratified by mammography history.
Results are based on a cohort of women who had received mammographic evaluations.
African-American women are less likely to receive adequate mammographic screening than white women, which may explain the higher prevalence of advanced breast tumors among African-American women. Tumor characteristics may also contribute to differences in cancer outcomes because African-American women have higher-grade tumors than white women regardless of screening. These results suggest that adherence to recommended mammography screening intervals may reduce breast cancer mortality rates.

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    • "The cancer-care-continuum disparities model begins with prevention and early detection and continues through the survival period. Several of the factors that may contribute to cancer disparities may occur at each end of the continuum or at the stages in between, such as diagnosis and treatment [14,18,23,24]. This study was unable to address the long-term clinical significance of the delay in follow up after an abnormal gastric cancer screening result; however, similar differences at other points along the cancer-care continuum may have a cumulative clinically significant overall impact on mortality. "
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    ABSTRACT: Background The prognosis for an abnormal medical finding is affected by both early detection and adherence to the presecribed schedule for follow-up examinations. In this study, we examined the time to follow up after an abnormal finding and determined the risk factors related to delays in follow up in a population-based screening program. Methods The study population consisted of patients who were newly diagnosed with gastric cancer through a gastric cancer screening program sponsored by the National Cancer Screening Program (NCSP) in 2005. Due to the skewed nature of the distribution of time to follow up, medians and interquartile ranges (IQR) are presented, and we analyzed the number of days preceding the follow-up time as a binary variable (≤90 days or >90 days). We used logistic regression analyses to evaluate the risk factors for a long delay. Results The median number of days to follow-up initiation after an abnormal finding was 11 (IQR 7–27); 13.9% of the patients with gastric cancer obtained their follow-up evaluation more than 90 days. Age, type of health insurance, screening method, and screening results were risk factors for delays in follow up. Conclusions This study examined delays from the time of the discovery of an abnormal finding to time of the follow-up evaluation. Because inadequate follow up of abnormal exam results undermines the potential benefits of cancer screening, it is important to organize services that minimize delays between cancer screening and treatment.
    Full-text · Article · Sep 2012 · BMC Cancer
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    • "In the United States, recent survival studies show that black women are more likely to be diagnosed with breast cancer at advanced stages compared with white women [15,18,19,21], and are less likely to have timely follow-up of abnormal mammography findings [22-24]. This suggests that the observed incidence-mortality paradox may be due to the lack of adequate mammography screening and diagnostic follow-up among black women [21]. "
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    ABSTRACT: Breast cancer screening rates have increased over time in the United States. However actual screening rates appear to be lower among black women compared with white women. To assess determinants of breast cancer screening among women in Michigan USA, focusing on individual and neighborhood socio-economic status and healthcare access. Data from 1163 women ages 50-74 years who participated in the 2008 Michigan Special Cancer Behavioral Risk Factor Survey were analyzed. County-level SES and healthcare access were obtained from the Area Resource File. Multilevel logistic regression models were fit using SAS Proc Glimmix to account for clustering of individual observations by county. Separate models were fit for each of the two outcomes of interest; mammography screening and clinical breast examination. For each outcome, two sequential models were fit; a model including individual level covariates and a model including county level covariates. After adjusting for misclassification bias, overall cancer screening rates were lower than reported by survey respondents; black women had lower mammography screening rates but higher clinical breast examination rates than white women. However, after adjusting for other individual level variables, race was not a significant predictor of screening. Having health insurance or a usual healthcare provider were the most important predictors of cancer screening. Access to healthcare is important to ensuring appropriate cancer screening among women in Michigan.
    Full-text · Article · Mar 2012 · International Journal for Equity in Health
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    • "For example, in New York City the Black:White breast cancer disparity in 2005 was 37% (Whitman et al, 2011). These data suggest that Black women in Chicago are not benefiting from the technological advancements that have been made in early detection and treatment over the last two decades (Berry et al, 2005; Smith-Bindman et al, 2006; Tehranifar et al, 2009). "

    Full-text · Chapter · Mar 2012
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