Breast cancer and screening in American Indian and Alaska Native women

Differences in Breast Cancers Among American Indian/Alaska Native and non-Hispanic Whites in the USA

IMPORTANCE

Breast cancer (BC) death rates have not improved for American Indian/Alaska Native (AI/AN) women, whereas, it has significantly decreased for non-Hispanic White (White) women.

OBJECTIVE

Delineate the differences in patient and tumor characteristics among AI/AN and Whites with BC, and its impact on age and stage at diagnosis as well as overall survival (OS).

METHODS

Hospital-based, cohort study using the National Cancer Database to identify female AI/AN and Whites diagnosed with BC between the years 2004 and 2016.

RESULTS

BC in 6866 AI/AN (0.3%) and 1,987,324 Whites (99.7%) were studied. The median age at diagnosis was 58 for AI/AN and 62 for Whites. AI BC patients traveled double the distance for treatment, lived in lower median income zip codes, had a higher percentage of uninsured, higher comorbidities, lower percentage of Stage 0/I, larger tumor size, greater number of positive lymph nodes, higher proportion of triple negative and HER2-positive BC than Whites. All the above comparisons were significant, p<0.001. Association between patient/tumor characteristics with age and stage at diagnosis was not significantly different between AI/AN and Whites. Unadjusted OS was worse for AI/AN as compared to Whites (HR=1.07, 95% CI=1.01-1.14, p=0.023). After adjustment of all covariates, OS was not different (HR=1.038, 95%CI=0.902-1.195, p=0.601).

CONCLUSION

There were significant differences in patient/tumor characteristics among AI/AN and White BC which adversely impacted OS in AI/AN. However, when adjusted for various covariates, the survival was similar, suggesting that the worse survival in AI/AN is mostly the impact of known biological, socio-economic, and environmental determinants of health.

Disparities in Postmastectomy Reconstruction Use among American Indian and Alaska Native Women

BACKGROUND

American Indian/Alaska Native (AI/AN) breast cancer patients undergo postmastectomy reconstruction (PMR) infrequently relative to non-Hispanic White (NHW) patients. Factors associated with low PMR rates among AI/AN women are poorly understood. The authors sought to describe factors associated with this disparity in surgical care.

METHODS

A retrospective cohort study of the National Cancer Database (2004 to 2017) identified AI/AN and NHW women, aged 18 to 64, who underwent mastectomy for stage 0 to III breast cancer. Patient characteristics, annual PMR rates, and factors associated with PMR were described with univariable analysis, the Cochran-Armitage test, and multivariable logistical regression.

RESULTS

A total of 414,036 NHW and 1980 AI/AN women met inclusion criteria. Relative to NHW women, AI/AN women had more comorbidities (20% versus 12%; Charlson Comorbidity Index ≥ 1; P < 0.001), had nonprivate insurance (49% versus 20%; P < 0.001), and underwent unilateral mastectomy more frequently (69% versus 61%; P < 0.001). PMR rates increased over the study period, from 13% to 47% for AI/AN women and from 29% to 62% for NHW women ( P < 0.001). AI/AN race was independently associated with decreased likelihood of PMR (OR, 0.62; 95% CI, 0.56 to 0.69). Among AI/AN women, decreased likelihood of PMR was significantly associated with older age at diagnosis, more remote year of diagnosis, advanced disease (tumor size >5 cm, positive lymph nodes), unilateral mastectomy, nonprivate insurance, and lower educational attainment in patient's area of residence.

CONCLUSIONS

PMR rates among AI/AN women with stage 0 to III breast cancer have increased, yet they remain significantly lower than rates among NHW women. Further research should elicit AI/AN perspectives on PMR, and guide early breast cancer detection and treatment.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Risk, II.

Racial/Ethnic Differences in Pathologic Complete Response to Neoadjuvant Chemotherapy and Survival Among Early-Stage, Erb-B2 Receptor Tyrosine Kinase 2-Low Breast Cancer Patients

Racial/ethnic differences in pathologic complete response (pCR), and in overall survival (OS) by pCR status, among early-stage, erb-b2 receptor tyrosine kinase 2 (ERBB2)-low breast cancer patients after neoadjuvant chemotherapy (NACT) are unknown. Data were from the 2010-2020 National Cancer Database that included Asian/Pacific Islander (API), American Indian/Alaska Native/Other (AIANO), Black, Hispanic, and White patients. pCR and OS were modeled using logistic regression and Cox regression, respectively. Of 25,577 patients, Black patients achieved a 17.4% pCR rate, Hispanic 16.0%, White 14.7%, API 13.5%, and AIANO 10.9%. AIANO patients had lower odds of pCR than White patients (adjusted odds ratio, 0.66; 95% confidence interval [CI], 0.48-0.91). Among patients without pCR, API (adjusted hazard ratio [aHR], 0.62; 95% CI, 0.51-0.76) and Hispanic (aHR, 0.77; 95% CI, 0.67-0.89) patients had lower mortality risks than White patients. Among patients with pCR, similar OS rates were observed between Hispanic (aHR, 1.08; 95% CI, 0.66-1.78), Black (aHR, 0.77; 95% CI, 0.55-1.09), API (aHR, 0.41; 95% CI, 0.15-1.12), or AIANO (aHR, 0.35; 95% CI, 0.05-2.50) and White patients. Post-NACT pCR rates were similar across racial/ethnic groups of early-stage, ERBB2-low breast cancer patients. Among patients without pCR, API and Hispanic patients had better OS; among patients with pCR, there was no differential OS by race/ethnicity. Our findings suggest the need for longitudinal studies of OS differences in this patient population.

Incidence of selected cancers in Non-Hispanic American Indian and Alaska Native adolescent and young adult populations, 1999-2019

PURPOSE

Studies have highlighted geographic variation in cancer incidence rates among American Indian and Alaska Native (AI/AN) populations. This is the first study to comprehensively evaluate incidence rates and trends among non-Hispanic AI/AN (NH-AI/AN) adolescents and young adults (AYAs) ages 15-39 years.

METHODS

Using the United States Cancer Statistics AI/AN Incidence Analytic Database, we identified all malignant cancer cases for NH-AI/AN AYA populations for the years 1999-2019. We calculated age-adjusted incidence rates (per 100,000) for NH-AI/AN populations overall, by region, and by age group. We calculated the total percent change in the incidence of leading AYA cancers between 1999 and 2019, and trends by region and cancer type using Joinpoint analysis.

RESULTS

Testicular (13.6) and breast (19.0) cancers had the highest incidence of all AYA cancers in NH-AI/AN males and females, respectively. Overall AYA cancer rates increased by 1.4% in NH-AI/AN males and 1.8% in NH-AI/AN females annually between 1999 and 2019. Increases were observed by age group and geographic region.

CONCLUSIONS

This study describes regional differences in incidence rates of AYA cancers among NH-AI/AN populations. This data can help inform resource and cancer control priorities and strategies to reduce cancer risk and enhance access to quality diagnostic and treatment services for this population.

Breast Cancer Screening and Outcomes Disparities Persist for Native American Women

Over the past three decades, mortality rates from breast cancer have decreased for multiple racial groups but have remained constant for American Indian and Alaskan Native (AI/AN) women. Additionally, AI/AN women are less likely to receive timely breast cancer screening and are more likely to be diagnosed with advanced stage breast cancer at younger ages than their White counterparts. These disparities can be explained, in part, by the unique barriers to accessing care faced by AI/AN women. The Indian Health Service provides care to many AI/AN patients; however, their scope of practice is limited, and the service is chronically underfunded, leaving many women without appropriate and timely care. Additionally, geographic access to care is limited because of the sparsity of clinics and limited transportation resources. American Indian and Alaskan Native patients also harbor a history of mistrust in health care systems, and there is a paucity of culturally sensitive education regarding the importance of screening. There have been some grassroots efforts to address these barriers; however, large-scale coordinated efforts are lacking. In order to provide equitable breast health care, more awareness and widescale initiatives are needed and can be championed by breast radiologists.

Cancer survival in the United States 2007-2016: Results from the National Program of Cancer Registries

BACKGROUND

Cancer survival has improved for the most common cancers. However, less improvement and lower survival has been observed in some groups perhaps due to differential access to cancer care including prevention, screening, diagnosis, and treatment.

METHODS

To further understand contemporary relative cancer survival (one- and five- year), we used survival data from CDC's National Program of Cancer Registries (NPCR) for cancers diagnosed during 2007-2016. We examined overall relative cancer survival by sex, race and ethnicity, age, and county-level metropolitan and non-metropolitan status. Relative cancer survival by metropolitan and non-metropolitan status was further examined by sex, race and ethnicity, age, and cancer type.

RESULTS

Among persons with cancer diagnosed during 2007-2016 the overall one-year and five-year relative survival was 80.6% and 67.4%, respectively. One-year relative survival for persons living in metropolitan counties was 81.1% and 77.8% among persons living in non-metropolitan counties. We found that persons who lived in non-metropolitan counties had lower survival than those who lived in metropolitan counties, and this difference persisted across sex, race and ethnicity, age, and most cancer types.

CONCLUSION

Further examination of the differences in cancer survival by cancer type or other characteristics might be helpful for identifying potential interventions, such as programs that target screening and early detection or strategies to improve access to high quality cancer treatment and follow-up care, that could improve long-term outcomes.

IMPACT

This analysis provided a high-level overview of contemporary cancer survival in the United States.

Disparities at the Intersection of Race and Ethnicity: Examining Trends and Outcomes in Hispanic Women With Breast Cancer

PURPOSE

We sought to examine tumor subtype, stage at diagnosis, time to surgery (TTS), and overall survival (OS) among Hispanic patients of different races and among Hispanic and non-Hispanic (NH) women of the same race.

METHODS

Women 18 years of age or older who had been diagnosed with stage 0-IV breast cancer and who had undergone lumpectomy or mastectomy were identified in the National Cancer Database (2004-2014). Tumor subtype and stage at diagnosis were compared by race/ethnicity. Multivariable linear regression and Cox proportional hazards modeling were used to estimate associations between race/ethnicity and adjusted TTS and OS, respectively.

RESULTS

A total of 44,374 Hispanic (American Indian [AI]: 79 [0.2%]; Black: 1,011 [2.3%]; White: 41,126 [92.7%]; Other: 2,158 [4.9%]) and 858,634 NH women (AI: 2,319 [0.3%]; Black: 97,206 [11.3%]; White: 727,270 [84.7%]; Other: 31,839 [3.7%]) were included. Hispanic Black women had lower rates of triple-negative disease (16.2%) than did NH Black women (23.5%) but higher rates than did Hispanic White women (13.9%; P < .001). Hispanic White women had higher rates of node-positive disease (23.2%) versus NH White women (14.4%) but slightly lower rates than Hispanic (24.6%) and NH Black women (24.5%; P < .001). Hispanic White women had longer TTS versus NH White women regardless of treatment sequence (adjusted means: adjuvant chemotherapy, 42.71 v 38.60 days; neoadjuvant chemotherapy, 208.55 v 201.14 days; both P < .001), but there were no significant racial differences in TTS among Hispanic patients. After adjustment, Hispanic White women (hazard ratio, 0.77 [95% CI, 0.74 to 0.81]) and Black women (hazard ratio, 0.75 [95% CI, 0.58 to 0.96]) had improved OS versus NH White women (reference) and Black women (hazard ratio, 1.15 [95% CI, 1.12 to 1.18]; all P < .05).

CONCLUSION

Hispanic women had improved OS versus NH women, but racial differences in tumor subtype and nodal stage among Hispanic women highlight the importance of disaggregating racial/ethnic data in breast cancer research.

Health Care Disparities in Radiology-A Review of the Current Literature

INTRODUCTION

Health care disparities exist in all medical specialties, including radiology. Raising awareness of established health care disparities is a critical component of radiology's efforts to mitigate disparities. Our primary objective is to perform a comprehensive review of the last 10 years of literature pertaining to disparities in radiology care. Our secondary objective is to raise awareness of disparities in radiology.

METHODS

We reviewed English-language medicine and health services literature from the past 10 years (2010-2020) for research that described disparities in any aspect of radiologic imaging using radiology search terms and key words for disparities in OVID. Relevant studies were identified with adherence to the guidelines set forth by the Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement.

RESULTS

The search yielded a total 1,890 articles. We reviewed the citations and abstracts with the initial search yielding 1,890 articles (without duplicates). Of these, 1,776 were excluded based on the criteria set forth in the methods. The remaining unique 114 articles were included for qualitative synthesis.

DISCUSSION

We hope this article increases awareness and inspires action to address disparities and encourages research that further investigates previously identified disparities and explores not-yet-identified disparities.

Development and Evaluation of a Cancer Literacy Intervention to Promote Mammography Screening Among Navajo Women: A Pilot Study

PURPOSE

Develop and evaluate a mammography intervention that provides hope about cancer prevention and treatment.

DESIGN

Pilot randomized controlled trial.

SETTING

Two communities on the Navajo Nation.

PARTICIPANTS

Navajo women and support persons.

INTERVENTION

Both groups received standard care: one home visit discussing mammography pros/cons and barriers. The treatment group received an intervention based on Navajo language via an additional home visit with health education materials (written and oral) in English and Navajo, including a Navajo Cancer Glossary with a new descriptive phrase for cancer.

ANALYSIS

Between control and intervention conditions, we compared baseline sociodemographics; changes from baseline to 3 months on mammography completion and breast cancer literacy scores.

MEASURES

(1) intervention feasibility; (2) self- and clinic-reported mammography screening completion; (3) breast cancer literacy.

RESULTS

A total of 25 participants were randomly assigned (13 treatment, 12 control), with 7 support persons in each arm. Mean age was 53 years, 90% had a high school degree or higher, 86% spoke Navajo and English. At 3 months, 44% had a clinically verified mammogram. Mammography completion was 57% among those with a support person and 27% among those without (P = .14). Intervention women reported more breast cancer beliefs consistent with mammography (P = .015).

CONCLUSIONS

Increases in breast cancer beliefs consistent with mammography show promise. Findings highlight a need to tailor education materials to Navajo culture/language and focus on enhancing support.

Andersen's Behavioral Model to Identify Correlates of Breast Cancer Screening Behaviors among Indigenous Women

This study examined predictive models of utilization of mammograms among Indigenous women adapting Andersen's behavioral model. Using a sample of 285 Indigenous women residing in South Dakota, nested logistic regression analyses were conducted to assess predisposing (age and marital status), need (personal and family cancer history), and enabling factors (education, monthly household income, mammogram screening awareness, breast cancer knowledge, self-rated health, and cultural practice to breast cancer screening). Results indicated that only 55.5% of participants reported having had a breast cancer screening within the past 2 years. After controlling for predisposing and need factors, higher education, greater awareness of mammogram, and higher utilization of traditional Native American approaches were significant predictors of mammogram uptake. The results provide important implications for intervention strategies aimed at improving breast cancer screening and service use among Indigenous women.

Breast cancer literacy and health beliefs related to breast cancer screening among American Indian women

The purpose of this article is to examine the health beliefs and literacy about breast cancer and their relationship with breast cancer screening among American Indian (AI) women. Using the Health Belief Model (HBM) and hierarchical logistic regression with data from a sample of 286 AI female adults residing in the Northern Plains, we found that greater awareness of breast cancer screening was linked to breast cancer screening practices. However, perceived barriers, one of the HBM constructs, prevented such screening practices. This study suggested that culturally relevant HBM factors should be targeted when developing culturally sensitive breast cancer prevention efforts.

Availability of prior mammograms affects incomplete report rates in mobile screening mammography

PURPOSE

Mobile mammography can improve access to screening mammography in rural areas and underserved populations. We evaluated the frequency of incomplete reports in mobile mammography screening and the relationships between prior mammograms and recall rates.

METHODS

The frequency of incomplete mammogram reports, the subgroups of those needing prior comparison mammograms, recalls for additional imaging, and availability of prior mammograms of a mobile screening mammography unit were compared with fixed site mammography from January 1, 2007 through December 31, 2009. All mobile unit mammograms were full field digital mammography (FFDM). Differences between rates of recall, incomplete reports, and availability of prior mammograms were calculated using the Chi-Square statistic.

RESULTS

Of 2640 mobile mammography cases, 21.9% (578) reports were incomplete, versus 15.2% (7653) (p ≤ 0.001) of 50325 fixed site reports. Of incomplete cases, recall for additional imaging occurred among 8.3% (218) of mobile mammography reports versus 11.3% (5708) (p ≤ 0.001) of fixed site reports. Prior mammograms were needed among 13.6% (360) of mobile mammography versus 3.9% (1945) (p ≤ 0.001) of fixed site reports. Mobile mammography recall rate varied with availability of prior mammograms: 16.0% (54) when no prior mammograms, 7.6% (127) when prior mammograms were elsewhere but unavailable and 5.9% (37) when prior FFDM were immediately available (p ≤ 0.001).

CONCLUSIONS

Incomplete reports were more frequent in mobile mammography than the fixed site. The availability of prior comparison mammograms at time of interpretation decreased the rate of incomplete mammogram reports. Recall rates were higher without prior comparison mammograms and lowest when comparison FFDM mammograms were available.

Cytochrome P450 Genetic Variation Associated with Tamoxifen Biotransformation in American Indian and Alaska Native People

Despite evidence that pharmacogenetics can improve tamoxifen pharmacotherapy, there are few studies with American Indian and Alaska Native (AIAN) people. We examined variation in cytochrome P450 (CYP) genes (CYP2D6, CYP3A4, CYP3A5, and CYP2C9) and tamoxifen biotransformation in AIAN patients with breast cancer (n = 42) from the Southcentral Foundation in Alaska and the Confederated Salish and Kootenai Tribes in Montana. We tested for associations between CYP diplotypes and plasma concentrations of tamoxifen and metabolites. Only the CYP2D6 variation was significantly associated with concentrations of endoxifen (P = 0.0008) and 4-hydroxytamoxifen (P = 0.0074), tamoxifen's principal active metabolites, as well as key metabolic ratios. The CYP2D6 was also the most significant predictor of active metabolites and metabolic ratios in a multivariate regression model, including all four genes as predictors, with minor roles for other CYP genes. In AIAN populations, CYP2D6 is the largest contributor to tamoxifen bioactivation, illustrating the importance of validating pharmacogenetic testing for therapy optimization in an understudied population.

Predictors of regular mammography use among American Indian women in Oklahoma: a cross-sectional study

Background

There are significant disparities in breast cancer screening and survivorship between American Indian (AI) and non-Hispanic white women. This study aimed to identify the salient beliefs AI women from Oklahoma have on regular mammography screening, and to determine which beliefs and health- related practices are associated with past mammography screening behavior.

Methods

This study used an integrated model of the Theory of Planned Behavior as the guiding theoretical framework. Data were collected from 255 (mean age = 51 years, SD 7.64 years) AI women randomly selected from a rural Oklahoma medical clinic (response rate: 79%). Multivariate logistic regression was used to identify factors associated with self-reported past mammography within the last two years while controlling for demographic variables. Associations were summarized using odds ratios (OR), the ratio of the odds of past mammography per a 1-unit increase in continuous independent factor scales (subjective physician norm, cultural affiliation, fatalism, knowledge of mammography screening guidelines, and perceived behavior control barriers) or between groups defined by categorical variables, and 95% confidence intervals (CI).

Results

Of the participants, 65% (n = 167) reported a screening mammogram within the last two years. After adjustment for age and educational status, women with a higher total subjective-norm physician score (OR = 1.15, 95% CI: 1.06-1.24), a higher knowledge of mammography screening guidelines (OR = 1.52, 95% CI: 1.00-2.31), a family history of breast cancer (OR = 9.97, 95% CI: 3.05-32.62), or reporting an annual versus none or a single physician breast examination (OR = 5.57, 95% CI: 1.79-17.37) had a higher odds of past mammography. On the other hand, women who were more culturally affiliated (OR = 0.42, 95% CI: 0.24-0.74), perceived more barriers (OR = 0.86, 0.78-0.94), or had higher fatalistic attitudes toward breast cancer (OR = 0.90, 95% CI: 0.82-0.99) had lower odds of past mammography.

Conclusion

In the development of culturally-appropriate interventions promoting mammography among AI communities, emphasis could be put on the following: a) promoting clinic-related practices (e.g. physician recommendation, physician breast examination); b) promoting community-related practices (e.g. knowledge about mammography while eliminating fatalistic attitudes); and c) reducing environmental barriers.

Conducting a Feasibility Study in Women's Health Screening Among Women in a Pacific Northwest American Indian Tribe

Breast and cervical cancers continue to contribute to high cancer mortality rates in American Indian/Alaska Native women; culturally appropriate interventions are needed to influence screening behaviors and to reduce delays in obtaining care. In a pilot feasibility study designed to influence Pacific Northwest American Indian/Alaska Native women's health screening knowledge and behaviors (breast and cervical), we employed a community-based participatory research approach. Data from interviews with study participants, those involved in implementation of the study and observations were included in the analysis. Study questions focused on training of staff, recruitment of participants, and implementation of the protocol and data management. The complexities of translational, transcultural research and the importance of reporting pilot feasibility studies to the advancement of transcultural research are highlighted in the findings of this research effort.

Breast cancer mortality among American Indian and Alaska Native women, 1990-2009

OBJECTIVES

We compared breast cancer death rates and mortality trends among American Indian/Alaska Native (AI/AN) and White women using data for which racial misclassification was minimized.

METHODS

We used breast cancer deaths and cases linked to Indian Health Service (IHS) data to calculate age-adjusted rates and 95% confidence intervals (CIs) by IHS-designated regions from 1990 to 2009 for AI/AN and White women; Hispanics were excluded. Mortality-to-incidence ratios (MIR) were calculated for 1999 to 2009 as a proxy for prognosis after diagnosis.

RESULTS

Overall, the breast cancer death rate was lower in AI/AN women (21.6 per 100,000) than in White women (26.5). However, rates in AI/ANs were higher than rates in Whites for ages 40 to 49 years in the Alaska region, and ages 65 years and older in the Southern Plains region. White death rates significantly decreased (annual percent change [APC] = -2.1; 95% CI = -2.3, -2.0), but regional and overall AI/AN rates were unchanged (APC = 0.9; 95% CI = 0.1, 1.7). AI/AN women had higher MIRs than White women.

CONCLUSIONS

There has been no improvement in death rates among AI/AN women. Targeted screening and timely, high-quality treatment are needed to reduce mortality from breast cancer in AI/AN women.

Factors that influence mammography use among older American Indian and Alaska Native women

INTRODUCTION

American Indian and Alaska Native (AIAN) women have relatively high breast cancer mortality rates despite the availability of free or low-cost screening.

PURPOSE

This qualitative study explored issues that influence the participation of older AIAN women in mammography screening through tribally directed National Breast and Cervical Cancer Early Detection Programs (NBCCEDPs).

METHODS

We interviewed staff (n = 12) representing five tribal NBCCEDPs and conducted four focus groups with AIAN women ages 50 to 80 years (n = 33).

RESULTS

Our analysis identified four main areas of factors that predispose, enable, or reinforce decisions around mammography: financial issues and personal investments, program characteristics including direct services and education, access issues such as transportation, and comfort zone topics that include cultural or community-wide norms regarding cancer prevention.

CONCLUSION

This study has implications for nurse education and training on delivering effective mammography services and preventive cancer outreach and education programs in AIAN communities.

Assessment of mammography experiences and satisfaction among American Indian/Alaska Native women

BACKGROUND

American Indian/Alaska Native (AI/AN) women have lower breast cancer (BCA) screening and 5-year survival rates than non-Hispanic Whites. Understanding reasons for low screening rates is important to combatting later stage diagnoses. The purpose of this study was to assess mammography experiences and satisfaction among AI/AN women.

METHODS

Nine focus groups were held with rural (N = 15) and urban (N = 38) AI/AN women 40 years and older in Kansas and Kansas City, Missouri, living both near and far from Indian Health Service (IHS) and tribal facilities, to examine experiences and satisfaction with mammography. Transcripts were coded and themes identified using a community-based participatory research approach.

FINDINGS

Themes were classified under knowledge, communication, and awareness of BCA; barriers to mammography; mammogram facility size; impressions of mammogram technologist; motivations for getting a mammogram; and how to improve the mammogram experience. Participants had knowledge of prevention, but described cultural reasons for not discussing it and described better experiences in smaller facilities. Participants indicated having a mammogram technologist who was friendly, knowledgeable, respectful, competent, and explained the test was a determining factor in satisfaction. Other factors included family history, physician recommendation, and financial incentives. Barriers included transportation, cost, perceptions of prejudice, and time constraints. Participants on reservations or near IHS facilities preferred IHS over mainstream providers. Suggestions for improvement included caring technologists, better machines with less discomfort, and education.

CONCLUSIONS

Interventions to enhance the professionalism, empathy, and cultural awareness of mammogram technologists; reduce barriers; and provide positive expectations and incentives could improve satisfaction and compliance with screening mammography.

Adherence to screening mammography among American Indian women of the Northern Plains

Breast cancer is a burden for American Indian (AI) women who have younger age at diagnosis and higher stage of disease. Rural areas also have had less access to screening mammography. An Indian Health Service Mobile Women's Health Unit (MWHU) was implemented to improve mammogram screening of AI women in the Northern Plains. Our purpose was to determine the past adherence to screening mammography at a woman's first presentation to the MWHU for mammogram screening. Date of the most recent prior non-MWHU mammogram was obtained from mammography records. Adherence to screening guidelines was defined as the prior mammogram occurring 1-2 years before the first MWHU visit among women >41 years, and was the main outcome, whereas, age and clinic site were predictors. Adherence was compared with national data of the Breast Cancer Surveillance Consortium (BCSC). Among 1,771 women >41 years, adherence to screening mammography guidelines was 48.01 % among >65 years, 42.05 % among 50-64 years, 33.43 % among 41-49 years, and varied with clinic site (25.23-65.93 %). Age (p < 0.0001) and clinic site (p < 0.0001) were associated with adherence. Overall, adherence to screening mammography guidelines was found in 39.86 % (706/1771) of MWHU women versus 74.34 % (747,095/1,004,943) of BCSC women. The majority (60.14 %) of women at first presentation to the MWHU had not had mammograms in the previous 2 years, lower screening adherence than nationally (25.66 %). Adherence was lowest among women ages 41-49, and varied with clinic site. Findings suggest disparities in mammography screening among these women.