FormalPara Key Points

  • While breast cancer mortality rates have improved among US Black, White, and Hispanic populations, no improvements have occurred among American Indian and Alaska Native (AI/AN) women.

  • Unlike all other ethnic groups, breast cancer incidence rates among AI/AN women vary dramatically by geographic location; this disparity remains unexplained.

  • AI/AN women face much longer travel times to breast imaging services and lower access to breast conservation as a breast cancer treatment relative to other ethnic groups.

  • Strategies for overcoming the barriers to breast cancer screening for AI/AN are discussed, such as wider implementation of mobile mammography and enabling transportation to breast cancer specialists for state-of-the-art treatment with radiation therapy and lumpectomy.

Breast cancer is the second most common cancer in women and features may vary by age, risk factors, geographic location, and ethnicity. Breast cancer screening has established benefits, including the earlier detection of tumors; however, disparate messages remain—such as varying screening intervals and the age to begin screening. Other gaps may relate to irregular screening and delays in follow-up imaging after an abnormal screening result. Similar screening gap problems exist in other cancer tests, including for lung cancer, colon cancer, and Pap tests.

Screening is a helpful but imperfect way to detect cancer [1], and consistent compliance with screening is needed to be effective. Patients often do not receive breast cancer screening or follow-up care due to lack of provider recommendation, noncompliance with annual or biannual screening, lack of knowledge of guidelines, difficulties accessing healthcare systems, and other constraints, such as transportation, time, or personal issues. Furthermore, health disparity research in the American Indian and Alaska Native (AI/AN) population is hampered by regional differences and because AI/AN data are often aggregated or mixed with other ethnic groups. Additionally, racial misclassification has occurred in AI/AN medical records [2, 3].

Breast Cancer Rates Among AI/AN Women

Breast cancer incidence rates among AI/ANs in the USA vary persistently by geographic location. For example, incidence rates among Southern Plains and Alaskan AI/AN women are twice those of AI/AN women in the Southwest. The reasons for regional differences in breast cancer incidence among AI/AN women remain unknown [4].

Data indicate that 30% of breast cancers in AI/AN women occur before the age of 50, compared to 19% for non-Hispanic White (NHW) women. Furthermore, 73% of breast cancer cases in AI/AN women occur before 65 years, compared to 60% for NHW women [5]. Fewer cancers are diagnosed at early stage (localized disease without regional or distant metastases) for AI/AN women compared to NHW women [6], and the risk of invasive breast cancer among AI/AN women under 50 years is 1.46 times that of NHW women. AI/AN women also have higher ratios of invasive breast cancer (that has spread to adjacent breast tissues) and advanced breast cancer (metastatic disease is cancer that has spread to other sites beyond the breast) as compared to NHW women [7]. Furthermore, compared with NHW women, AI/AN women have an 8% higher mortality rate and a higher mortality to incidence (MIR) ratio across all age groups and geographic regions [8]. This indicates that, despite lower incidence rates, prognosis is worse in AI/AN women [9].

Although breast cancer mortality rates have decreased nationally by 40% among NHW and Black/African American women in the last several years, mortality rates among AI/AN women are unchanged since the 1990s [10]. AI/AN women have a worse prognosis post-diagnosis than other ethnic groups. These disparities may be due to the unequal distribution of mammography screening among AI/AN women nationally. It is not surprising, therefore, that breast cancer mortality rates have not decreased for AI/AN women.

Breast cancers are more prevalent among Native American women under the age of 50 compared to NHW women. Additionally, breast cancers are diagnosed at an early stage in Native American women as compared to White women [6].

Barriers to Early Detection

The 2018 National Health Interview Survey revealed that only 66% of AI/AN women aged 50–74 years underwent mammographic screening within 2 years prior to the survey, making this the lowest screening rate of all ethnic groups [10]. In addition, adherence to breast cancer screening varies among AI/AN women in different regions of the country.

The most commonly reported barriers to mammogram screening in this population are economic and geographic constraints (including cost, lack of insurance, location of screening, and transportation problems), cultural differences, mistrust of the American healthcare system, and deficiencies in the Indian Health Service (IHS) [11]. Access to screening mammography can be inconsistent, difficult, or limited, meaning that AI/AN women may not benefit from early detection of breast cancer.

Up to 40% of AI/ANs live on reservations and/or in rural locations, where access to mammography screening is limited. The IHS does not employ oncologists, and cancer care must be purchased and/or referred. Referrals to oncologists depend on funding from Congress. Although this disparity has been well-documented, there are few programs in place to address it [4]. In the absence of local mammography services, mammograms are frequently contracted to private facilities. However, if funding for external care is depleted or if patients do not meet eligibility criteria, then the cost of mammography screening becomes a barrier.

AI/AN women have reported 2–3 times longer travel to obtain mammography, which is the longest of any racial group. Among the new and more accurate breast imaging technologies, tomosynthesis and MRI are less often found in rural areas, further worsening screening disparities [12, 13]. In the absence of fixed mammography facilities in rural areas and small towns, mobile mammography screening can service under-represented populations in both rural and urban settings. However, few mobile units currently specifically serve AI/AN populations.

Socioeconomic and structural barriers impede access to mammography for AI women who commonly do not or cannot prioritize their non-urgent medical care or preventive care over family care priorities. Screening mammography is only the first step in early breast cancer detection. Approximately five additional appointments are required to complete diagnosis and treatment. Therefore, variations in access can substantially affect treatment decisions [14].

Limited Treatment Choices

AI/AN women are more likely to undergo mastectomy than lumpectomy, even in early stage disease, despite the decreased complications, decreased recovery time, and improved quality of life associated with lumpectomy [14]. One reason for this is the distances that AI/AN women have to travel for radiation therapy following lumpectomy.

Post-diagnosis, AI/AN women in some regions experience disparities in surgical treatment and are more likely to undergo mastectomy [14]. AI/AN women in the Northern Plains and Alaska are less likely to obtain surgical care concordant with guidelines, adjuvant therapy, chemotherapy, or post-therapy surveillance. In addition, they are likely to face more delays to their treatment and less surveillance [14]. Northern Plains and Alaska AI/AN women are more likely to have mastectomy compared to NHW women in the same region, suggesting that travel times may not be the determining factor in these choices. However, radiation therapy, an essential part of breast conservation with lumpectomy, requires multiple visits over several weeks, which can be a substantial barrier to patients living on rural Tribal lands. In North Dakota, for instance, breast cancer is associated with higher likelihood of mastectomy and lower likelihood of radiation therapy. In addition, across all AI/AN groups, post-treatment surveillance imaging and follow-up treatment are more limited [15].

Transportation, time off work for extended travel, or lower incomes limit access to breast conservation as well as follow-up screening or diagnostic mammography. Treatment with adjuvant endocrine therapy also may be compromised by travel times.

Overcoming Barriers to Timely Cancer Diagnosis and Treatment Choices

Access to breast cancer screening and other preventive care actions is a multidimensional issue, with input and actions from providers and the population needed to be successful. Equitable cancer screening ought to be a public health priority, especially among medically underserved populations that have higher risk of death and lower likelihood of follow-up care.

In order to improve access to breast cancer trials for AI/AN women, collaboration between academic centers, Tribes, mobile screening units, telemedicine, patient navigators, and providers of radiation therapy is needed [14].

Efforts to overcome cultural barriers to diagnosis and treatment have already been improved through the use of patient navigators who assist AI/AN women through detection, diagnosis, and treatment [16]. Patient navigators help to improve patient compliance and provide assistance with care in complex medical systems. Since 1995, the Native American Cancer Research Corporation has employed and trained patient navigators who have guided over 1000 cancer patients through breast cancer continuum [16]. The consistent use of community health navigators remains a challenge, with wide variability in training, roles and responsibilities, patient load, supervision, and credentials [16]. Standardized and appropriate training and credentialing should be put in place to ensure that the patient navigators and/or community health workers employed by or contracted to healthcare organizations are trained in culturally sensitive communication.

Patient education plays an important role in breast cancer screening adherence and follow-up. A study among Navajo women found that a home-based mammography intervention with culturally sensitive cancer education materials provided hope that steps can be taken to prevent and treat cancer. Results of this study suggest that women’s perceptions may have changed concerning the prevention and treatability of breast cancer [17].

To lower geographic access barriers, deploying imaging centers at convenient locations or launching and staffing mobile mammography units should be considered. Programs to encourage cancer screening, navigation, access to screening, and access to treatment are vital. Services such as the Great Plains Indian Health Service mammography program [18] or the Hopi Cancer Support Service (a Tribal health program that promotes cancer screening among Hopi patients) [19] are model cancer prevention programs that should be expanded.

Healthcare providers should support and improve breast cancer screening and recommend additional screening for women at high risk. Access to genetic testing should also be expanded. Guidelines should be advertised and widely promoted to all communities and populations.

Interactions with land and territory are important and unique aspects of AI/AN cultures. Ideally, healthcare would move away from something that is done to AI/AN communities to something that is generated within these communities.

To address ongoing disparities in breast cancer detection and treatment among AI/AN women, community-based efforts are the best hope. Such efforts could be provided via reservations, municipalities, or virtually. Greater support for mobile mammography to reliably bring screening to underserved and rural communities is urgently needed.