Breast cancer is the most commonly diagnosed cancer and the second leading cause of cancer-related death (after lung and bronchial cancer) among women in the United States (1). In 2002, at least 182,125 women in the United States had a diagnosis of invasive breast cancer, and 41,514 died from the disease* (1). Screening mammography can reduce mortality from breast cancer by approximately 20%--35% in women aged 50--69 years and approximately 20% in women aged 40--49 years (2,3). Organizations including the American Medical Association, American College of Obstetricians and Gynecologists, and American Cancer Society support mammography screening beginning at age 40 years, although these groups vary in their recommendations regarding intervals for rescreening. The U.S. Preventive Services Task Force, an independent panel of private-sector experts in prevention and primary care convened by the Department of Health and Human Services, recommends that women aged >40 years be screened for breast cancer with a mammogram every 1--2 years (4). Although mammogram use increased substantially during the 1990s (5), results from a recent cohort study of health maintenance organization members revealed declining screening rates during 1999--2002 (6). This report describes Behavioral Risk Factor Surveillance System (BRFSS) findings that indicate a similar decreasing trend in self-reported use of mammograms among women aged >40 years during 2000--2005. Continued declines in mammography use might result in increased breast cancer mortality.
BRFSS is a state-based, random-digit--dialed telephone survey of the civilian, noninstitutionalized adult population. BRFSS data are weighted for probability of selection and to match the age-, race-, and sex-specific populations from annually adjusted intercensal estimates. During 2000--2005, adult female respondents were asked whether they had ever had a mammogram.† Respondents who answered "yes" were then asked how long it had been since their last mammogram. The response rate ranged from a mean of 49.0% to 57.9% among states that posed the mammography questions. The percentage of all women aged >40 years who reported having had a mammogram within the 2 years preceding the survey was calculated, with 95% confidence intervals (CIs), and estimates were age adjusted to the 2000 U.S. Census standard population of women. Logistic regression was used to assess the linear time trend, which was considered statistically significant if the beta coefficient for year was nonzero at p<0.01.
The total age-adjusted proportion of all women aged >40 years who were asked the BRFSS mammography questions each year and reported having had a mammogram within the 2 years preceding the survey decreased significantly from 76.4% (CI = 75.8--76.9) in 2000 to 74.6% (CI = 73.8--75.4) in 2005 (test for trend, p<0.001) (Table).
Reported by: AB Ryerson, MPH, J Miller, MD, CR Eheman, PhD, MC White, ScD, Div of Cancer Prevention and Control, National Center for Chronic Disease Prevention and Health Promotion, CDC.
Editorial Note:
Data from BRFSS indicate a statistically significant decline in the proportion of women aged >40 years during 2000--2005 who reported having had a mammogram in the preceding 2 years. Since 1999, U.S. women overall aged >40 years have met the Healthy People 2010 objective of 70% of women having received a mammogram in the preceding 2 years (objective 3-13) (7); however, the slight decline indicated by BRFSS data during 2000--2005 suggests a need to monitor mammography screening more carefully. Because mammography screening every 1--2 years can significantly reduce mortality from breast cancer (2--4), continued declines in mammography use might result in increased breast cancer mortality rates.
The reason for the apparent decline in screening mammography is unclear and might be attributable to a combination of factors. One study has indicated that breast-imaging facilities face challenges such as shortages of key personnel, malpractice concerns, and financial constraints (8). Because the number of U.S. women aged >40 years increased by more than 24 million during 1990--2000 (9), the number of available facilities and trained breast specialists might not be sufficient to meet the needs of the population, whose overall median age continues to increase. Previously, low mammography use has been associated with not having a usual source of health care, not having health insurance, and being a recent immigrant (10). However, until future studies confirm a decreasing trend in mammography rates and determine whether the trend affects all women or only certain subpopulations, determining the causes of this apparent decline will remain difficult.
The findings in this report are subject to at least five limitations. First, the results might overestimate actual breast cancer screening rates because BRFSS does not indicate the reason for the test; certain mammograms might have been used to assess specific breast symptoms or follow up after an abnormal finding during a clinical breast examination, rather than for routine screening. Second, because BRFSS is administered by telephone, only women in households with landline telephones are represented; therefore, the results might not be representative of all women. Third, responses are self-reported and not confirmed by review of medical records. Fourth, the survey response rate was low. Finally, data from 2001, 2003, and 2005 included only the states that implemented the optional Women's Health Module (which included the mammography questions) and might not be representative of the entire U.S. population. However, the test for a decreasing linear trend remained significant (p<0.001) for years in which all states participated (2000, 2002, and 2004).
CDC supports several nationwide initiatives related to breast cancer prevention and control. The National Breast and Cervical Cancer Early Detection Program (NBCCEDP) is administered by CDC through cooperative agreements with all 50 states, the District of Columbia, 13 American Indian/Alaska Native tribes and tribal organizations, and four U.S. territories. NBCCEDP provides low-income, uninsured, and underinsured women access to timely, high-quality breast and cervical cancer screening and diagnostic services. CDC also supports the National Comprehensive Cancer Control Program by funding states, territories, and tribes and tribal organizations to establish coalitions through which communities pool resources to reduce cancer risk, increase early detection, improve treatment, and increase survival rates. Finally, CDC's National Program of Cancer Registries collects surveillance data on cancer through 49 state and territorial registries in the United States so that public health professionals can better understand and address the U.S. occurrence of cancer and its effects. CDC will continue working through each of these programs and with external partners to emphasize the importance of mammography screening and rescreening to women and their health-care providers and will facilitate the increased use of effective community programs through federal and nonfederal partners. In addition, clinicians and community-based organizations should continue to encourage mammography screening and rescreening every 1--2 years for women aged >40 years.
Acknowledgment
This report is based, in part, on data contributed by state BRFSS coordinators.
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