Ethnic Differences in Mammography Use among Older Women: Overcoming the Barriers

Ethnicity is thought to be a significant factor in breast cancer. Although the incidence of the disease is lower among black women, mortality in this group is disproportionally high [1]. Improvements in mortality have been seen across all age and ethnic groups, but the 5-year disease-free survival rate among black women with breast cancer (69%) continues to lag behind that in white women (84%) [2]. Several studies [3, 4] show that older black women have substantially lower rates of mammography use and higher rates of late-stage breast cancer at diagnosis than their white counterparts. Whether this differential use of mammography explains the ethnic differences in stage at diagnosis has been the subject of ongoing debate [5, 6].

In this issue, McCarthy and colleagues present the results of their retrospective cohort study on the use of mammography and its link to stage at diagnosis among women 67 years of age and older [7]. Despite the retrospective nature of the data and the small number of black women (4%), the study adds to our understanding of mammography and breast cancer outcomes. It suggests that previous use of mammography is strongly and equally associated with stage at diagnosis in both black and white women 65 years of age and older. However, significantly more black women than white women did not use mammography (35% and 22%). A black-white stage differential is evident only in these mammography nonusers, and this excess in late-stage diagnosis persists despite adjustment for sociodemographic factors. The message is clear: All older women benefit equally from regular screening mammography, and its lower use by black women may help to explain the previously demonstrated excess of late-stage breast cancer diagnosis among these women.

McCarthy and colleagues raise two important issues. First, mammography use is clearly related to stage at diagnosis. In addition, the factors that affect mammography use are poorly understood but are surely influenced by sociodemographic and cultural factors.

Despite the clear evidence of the benefit of screening mammography [8-12], particularly in older women, and the increasing number of women of all ages participating in screening, mammography rates for older women remain low. The current study and other series consistently show age and ethnic differences in use of mammography, but extensive research in this area has not yet found the reasons for these differences.

Many barriers impede the use of screening mammography and other preventive health services [1, 13]. Cultural factors influence attitudes toward health care in general and preventive health in particular [14]. Economic factors encompass not only the cost of mammography but also costs of transportation, child care, and time off from work. Although many see Medicare coverage as a great equalizer, copayments and deductibles remain substantial financial barriers to mammography use, and comparisons of screening for breast and cervical cancer in Canada and the United States show that socioeconomic disparities in preventive care persist despite universal coverage [15, 16]. Nonfinancial features of availability and accessibility of the health care setting may also prevent women from having mammography [17, 18]. For example, whether or not the physician recommends screening mammography has a substantial impact on patients' use of screening services [19, 20].

If widespread access to breast cancer screening services is our goal, we must develop interventions targeted at these complex sociocultural and community-specific barriers. The Centers for Disease Control and Prevention-funded National Breast and Cervical Cancer Early Detection Program is one example of the resources and energy that are being funneled into this effort. This program is a comprehensive national effort that focuses on the populations at greatest risk-medically underserved and ethnic minority women who are 50 years of age and older [21]. From 1990 through 1997, the more than 8400 sites nationwide participating in the program have screened more than 590 000 women. The Susan B. Komen Foundation, the National Cancer Institute, the American Cancer Society, and others are also supporting programs to overcome barriers to mammography use among ethnic minority groups and socioeconomically disadvantaged persons. Although they focus on the provision of coordinated screening services, these programs also address public and professional education and patient navigation [14, 21]. Many of these programs, including our own in Camden, New Jersey, focus on use of community outreach interventions and development of active community coalitions to reach at-risk populations. By using local churches, community centers, and the homes of program participants formal and informal educational sessions and by developing novel educational strategies (such as the use of live theater), we and others have made inroads into the target communities [22]. Mobile mammography facilities can overcome some of the barriers that keep women away from traditional health care settings.

Although patient-oriented programs and community outreach have proven successful in reaching ethnically diverse populations, the role of the physician and other health care providers in encouraging mammography use is also critical. Referral for mammography from the health care provider has been shown to be a strong determinant of mammography use [19, 20]. Provision of preventive care to ethnic minority populations and poor persons poses special challenges to health care providers working under time constraints. However, by addressing the fears and misconceptions about mammography and breast cancer and by stressing the importance of routine mammography, the clinician is likely to improve the use of mammography by all women.

The explanations for the stage differences observed among women who have not had mammography are intriguing. For example, covariables that could not adequately be controlled for, such as education, access to health care in general, and use of preventive health strategies were not captured by the authors and may differentially influence black and white older women who do not use mammography. Other researchers [5] argue that biological differences in tumor behavior contribute to worse survival and excessive late-stage diagnosis among black women. Results from the National Cancer Institute Black/White Cancer Survival Study [23] and recent studies by Heimann and Roach and their coworkers [24, 25], however, suggest that differences in survival among ethnic groups are primarily attributable to such prognostic factors as tumor size, receptor status, number of lymph nodes, age, and use of adjuvant therapy. These studies suggest that when treatment is similar, differences in biological behavior are not likely to play a large role in explaining the differences in survival between ethnic groups. Rather, stage at diagnosis and the socioeconomic and cultural factors that influence survival seem to play the most crucial role. Just as survival with breast cancer is similar when comparable groups are analyzed, few data support the idea that tumor biology plays a role strictly in mammography nonusers and not in the group as a whole.

It is evident that differences in stage at diagnosis of breast cancer, although affected tremendously by mammography use, probably result from many contributing factors [5, 6]. Although differences in use of mammography helps explain differences in stage at diagnosis seen between black and white older women, the contribution of socioeconomic, sociodemographic, and cultural factors must be understood so that successful interventions can abolish differences in breast cancer outcome. Although McCarthy and colleagues' study stresses the importance of screening in older black women, screening is also important for other vulnerable groups, including Hispanic, Native American, and Asian women and women who lack education and insurance [14]. Successful strategies to reach these populations must be developed to achieve cancer control.

I concur with the McCarthy and colleagues' conclusion that mammography can benefit all older women through early-stage diagnosis of breast cancer. However, to harness the full benefit of early detection, we must understand and overcome barriers to mammography use in ethnic minority populations. In dealing with underserved populations, clinician must integrate preventive health strategies into everyday clinical practice, encourage mammography use, and use existing community programs that provide coordinated screening and follow-up services. Underserved populations present special challenges with regard to use of preventive health services, but success is possible with targeted strategies.

• Copyright ©2004 by the American College of Physicians