Vital Signs: Breast Cancer Screening Among Women Aged 50--74 Years --- United States, 2008

ABSTRACT

Background: Breast cancer remains the second leading cause of cancer deaths for women in the United States. Screening with treatment has lowered breast cancer mortality.

Methods: Every 2 years, CDC uses Behavioral Risk Factor Surveillance System data to estimate mammography prevalence in the United States. Up-to-date mammography prevalence is calculated for women aged 50--74 years who report they had the test in the preceding 2 years.

Results: For 2008, overall, age-adjusted, up-to-date mammography prevalence for U.S. women aged 50--74 years was 81.1%, compared with 81.5% in 2006. Among the lowest prevalences reported were those by women aged 50--59 years (79.9%), persons who did not finish high school (72.6%), American Indian/Alaska Natives (70.4%), those with annual household income <$15,000 (69.4%), and those without health insurance (56.3%). Highest mammography prevalence was among residents of the northeastern United States.

Conclusions: In recent years, mammography rates have plateaued. Critical gaps in screening remain for certain racial/ethnic groups and lower socioeconomic groups, and for the uninsured.

Implications for Public Health Practice: Health-care reform is likely to increase access by increasing insurance coverage and by reducing out-of-pocket costs for mammography screening. Widespread implementation of evidence-based interventions also will be needed to increase screening rates. These include patient and provider reminders to schedule a mammogram, use of small media (e.g., videos, letters, brochures, and flyers), one-on-one education of women, and reduction of structural barriers (e.g., more convenient hours and attention to language, health literacy, and cultural factors).

Breast cancer remains the most commonly diagnosed cancer and the second leading cause of cancer deaths among women in the United States. In 2006 (the most recent data available), approximately 191,410 women were diagnosed with invasive breast cancer, and 40,820 women died (1). The incidence and mortality have been declining since 1996 at a rate of approximately 2% per year (2), possibly as a result of widespread screening with mammography and the development of more effective therapies (3). Mammography use declined slightly in 2004, but rose again in 2006 (4,5). This Vital Signs report updates mammography screening prevalence in the United States, using data from the 2008 Behavioral Risk Factor Surveillance System (BRFSS).

Methods

BRFSS is a state-based, random-digit-dialed telephone survey of the civilian, noninstitutionalized adult population that collects information on health risk behaviors, preventive health practices, and health-care access in the United States (6). Every 2 years (even numbered years), adult female respondents are asked whether they have ever had a mammogram. Respondents who answer "yes" are then asked how long it has been since their last mammogram. For this report, breast cancer screening prevalence was calculated for women aged 50--74 years based on United States Preventive Services Task Force (USPSTF) recommendations, which considers women to be up-to-date if they received a mammogram in the preceding 2 years (7). Respondents who refused to answer, had a missing answer, or answered "don't know/not sure" were excluded.

The median Council of American Survey and Research Organizations (CASRO) response rate was 53.3%, and the median CASRO cooperation rate was 75.0% (6). Data were weighted to the age, sex, and racial and ethnic distribution of each state's adult population using intercensal estimates and were age-standardized to the 2008 BRFSS female population.

Results

In 2008, the BRFSS survey was administered to 414,509 respondents, of whom 120,095 were women aged 50--74 years. The age-adjusted prevalence of up-to-date mammography for women overall in the United States was 81.1% (Table). Among the lowest prevalences reported were those by women aged 50--59 years (79.9%), persons who did not finish high school (72.6%), American Indian/Alaska Natives (70.4%), those with annual household income <$15,000 (69.4%), and those without health insurance (56.3%). Mammography screening prevalence varied by state, with the highest mammography use in the northeastern United States. Among states, screening prevalence ranged from 72.1% in Nevada to 89.8% in Massachusetts (Figure 1). Nationally, up-to-date mammography screening increased from 77.5% in 1997 to 81.1% in 2008 (Figure 2).

Conclusions and Comment

After mammography was shown to be effective in lowering morbidity and mortality from breast cancer in the early 1990s, it was adopted rapidly for the early detection of breast cancer (3). However, as this Vital Signs report confirms, mammography utilization has leveled off in the last decade (4,5). Other population-based surveys have shown a similar plateau in rates. Results from the 2008 National Health Interview Survey indicate comparable mammography screening for women aged 50--64 and 65--74 years (74.2% and 72.6%, respectively)(4).

In 2000, the U.S. Department of Health and Human Services set a Healthy People 2010 target to increase to 70% the proportion of women aged >40 years who had a mammogram within the past 2 years.* The target was met in 2003 and exceeded by 11 percentage points in 2008. Nonetheless, approximately 7 million eligible women in the United States are not being screened regularly, and they remain at greater risk of death from breast cancer. One recent report estimated that as many as 560 breast cancer deaths could be prevented each year with each 5% increase in mammography (8). One successful program that reaches out to minority, low income, uninsured women is the National Breast and Cervical Cancer Early Detection Program.† The program has provided high quality screening, diagnostic and treatment services for the past 20 years.

Mammography utilization is influenced by multiple factors, including patient and provider characteristics, health-care norms, and access to and availability of health-care services. Similar to previous analyses, the analysis in this report found pockets of mammography underscreening among several large U.S. populations. For example, the screening rate varied considerably by geography and was lowest in west-central states, the states with the lowest population densities§ as well as the states with the fewest mammography facilities.¶ A study from Texas highlighted the association between mammography supply and mammography use at the county level. Counties with no mammography units had the lowest mammography utilization (9).

The passage of the Patient Protection and Affordability Act should remove the financial barrier to mammography screening by expanding coverage and eliminating cost sharing in Medicare and private plans; however, barriers remain. For example, in 2008 the difference in mammography prevalence between women with and without health insurance was 27.5%. Even among women with health insurance, 16.2% had not received mammography in the preceding 2 years. Similar differences in receipt of mammography by insurance status were noted in a 2009 study (9). These findings suggest new roles for public health to improve screening through increased education of women and providers, and through additional targeted outreach to underscreened groups including lower SES, uninsured and select minority groups. Several evidence-based interventions are recommended by the Guide to Community Preventive Services to increase mammography screening in communities.** These include sending client reminders to women, using small media (e.g., videos, letters, flyers, and brochures), and reducing structural barriers (e.g., providing more convenient hours and increasing attention to language, health literacy, and cultural factors). Surveillance with targeted outreach, case management, and quality assurance through systems change are productive future roles for public health agencies to improve the delivery of clinical preventive services in the era of health reform.

The findings in this report are subject to at least three limitations. First, because BRFSS is a telephone survey of residential households, only women in households with landline telephones participated; therefore, the results might not be representative of all women. Second, responses are self-reported and not confirmed by review of medical records. Finally, the survey response rate was low, which increases the risk for response bias.

Many factors influence a woman's intent and ability to access screening services, including socioeconomic status, awareness of the benefits of screening, and mammography acceptability and availability (10). However, the most common reason women give for not having a mammogram is that no one recommended the test; therefore, health-care providers have the most important role in increasing the prevalence of up-to-date mammography among women in the United States (10).

Reported by

LC Richardson, MD, SH Rim, MPH, M Plescia, MD, Div of Cancer Prevention and Control, National Center for Chronic Disease Prevention and Health Promotion, CDC.

References

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6. CDC. Behavioral Risk Factor Surveillance System. Atlanta, GA: US Department of Health and Human Services, CDC; 2010. Available at http://www.cdc.gov/brfss. Accessed June 20, 2010.
7. US Preventive Services Task Force. Screening for breast cancer: recommendation statement. Rockville, MD: Agency for Healthcare Research and Quality; 2009. Available at http://www.ahrq.gov/clinic/uspstf09/breastcancer/brcanrs.htm. Accessed June 20, 2010.
8. Farley TA, Dalal MA, Mostashari F, Frieden TR. Deaths preventable in the U.S. by improvements in use of clinical preventive services. Am J Prev Med 2010;38:600--9.
9. Elting LS, Cooksley CD, Bekele BN, et al. Mammography capacity impact on screening rates and breast cancer stage at diagnosis. Am J Prev Med 2009;37:102--8.
10. Schueler KM, Chu PW, Smith-Bindman R. Factors associated with mammography utilization: a systematic quantitative review of the literature. J Womens Health 2008;17:1477--98.

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