Original Research
Vol. 4, Issue 2, 2024 · P1-11
Access to National Cancer Institute-Designated Cancer Centers Among Native American Cancer Patients
Haoran Li, MD, PhD,Xiaohui Liu, PhD,Georges Gebrael, MD,Yeonjung Jo, MS,Neeraj Agarwal, MD, FASCO,Kamal K Sahu, MD,Benjamin L Maughan, MD,Umang Swami, MD
Submission received: 2024-08-17 / Accepted: 2024-09-09 / Published: 2024-10-11
Abstract
Introduction/Purpose
Native Americans (NAs) are subject to high cancer mortality rates in the USA. Despite that, they face significant geographic barriers to access to cancer care. This study aims to estimate the travel distance to a National Cancer Institute (NCI)-designated cancer center for NA patients in Utah and the continental USA.
Methods
This IRB-approved study utilized retrospective data on genitourinary cancer patients from both NAs and white populations from February 2013 to January 2023. The distance of their geographical location to the Huntsman Cancer Institute (HCI) at the University of Utah was calculated using their home zip code and a GeoData ZIP Code Distance Calculations Matrix Template. A shapefile containing NCI-designated cancer centers was used alongside the Area Deprivation Index (ADI), matched to block groups from the 2020 census, to serve as a national control group. All geographic data was visualized in ArcGIS 10.7 by using the coordinates and a 5-digit zip code tabulation area to map locations.
Results
A total of 468 NA patients were eligible and included. The median travel distance for NA patients vs. white patients to HCI was 190.6 miles (range: 1.1-596.4 miles) vs. 21.6 miles (range: 1.1-269 miles, p<0.0001). In the continental US, the median travel distance from NA reservations vs. ADI-matched block groups to the nearest NCI-designated cancer centers was 186.5 miles (range 77.8-629 miles) vs. 159 miles (range 1.9-671.3 miles, p<0.01).
Conclusion
The travel distance to NCI-designated cancer center for NA cancer patients in Utah was around nine times longer than that of white cancer patients. This study highlights the significant disparity in cancer care accessibility faced by NA communities.
Take Home Messages
1. Native Americans are subject to high cancer mortality rates in the United States.
2. In this study, the travel distance to a National Cancer Institute-designated cancer center for Native American cancer patients in Utah was around nine times longer than that of white cancer patients.
3. In the continental United States, the median travel distance from Native American reservations to the nearest National Cancer Institute-designated cancer centers was significantly longer than that of Area Deprivation Index-matched block groups.
4. This study highlights the disparity in cancer care accessibility faced by Native American cancer patients, stressing the need for healthcare policies to mitigate these disparities.
Introduction
Cancer continues to be a significant public health challenge in the United States, disproportionately affecting various racial and ethnic groups. Native Americans, in particular, experience some of the highest mortality rates from cancer compared to other populations.1 Multiple factors contribute to these disparities, including socioeconomic status, access to healthcare, and environmental factors.2
Despite advances in cancer prevention, diagnosis, and treatment, Native American communities continue to face a significant burden of cancer-related morbidity and mortality. According to the American Cancer Society (ACS), the cancer death rate for Native Americans is higher than that of non-Hispanic whites, with lung, prostate, and colorectal cancers being the leading causes of cancer-related deaths among Native American men, and lung, breast, and colorectal cancers accounting for the highest mortality rates among Native American women.3 Furthermore, cancer incidence rates were significantly higher among American Indians and Alaska Natives compared to Whites between 2014 and 2018 (488.3 vs. 477.9 per 100,000 non-Hispanic persons, age-adjusted to the 2000 US standard population, relative risk 1.02).4 Additionally, Native Americans have been found to experience lower five-year cancer survival rates compared to non-Hispanic whites for most cancer types.5 The elevated cancer mortality rates among Native Americans can be partially attributed to lower cancer screening rates, later-stage cancer diagnoses, and limited access to high-quality cancer care.6 Additionally, Native American populations face unique challenges, such as geographic barriers, cultural differences, and historical mistrust of the healthcare system, further exacerbating the disparities in cancer outcomes.7 Regarding cancer treatment, a previous survey among American Indians and Alaska Natives with cancer showed that, despite these patients showing trust in their treating physicians, they frequently reported non-adherence to the planned treatment (26%), and mostly for non-clinical reasons.8 The plausible causes for this clinical non-adherence include lack of proper education about cancer, geographic isolation, mistrust of healthcare providers, discrimination, and dissatisfaction with the clinical decision-making process. For instance, in breast cancer, Native Americans and Alaska Natives were more likely to decline surgery and chemotherapy compared to White patients.9 Furthermore, a previous report suggested that, in addition to structural and physical barriers preventing optimal cancer symptom management, cultural barriers existed among American Indians and Alaska Natives and included challenges in integrating illness beliefs, historic healing practices, and the use of traditional healers.10
Geographic barriers significantly contribute to the disparities in cancer care access and outcomes among Native American populations.11 Many Native American reservations are located in rural areas, often far from comprehensive cancer care facilities, including National Cancer Institute (NCI)-designated cancer centers.12 These centers offer state-of-the-art cancer treatments, clinical trials, and multidisciplinary care, all of which are critical for improving cancer outcomes.13 Travel distance to healthcare facilities is a crucial determinant of access to cancer care, and longer distances have been associated with decreased utilization of cancer-related services.14 Studies have found that rural cancer patients, including Native Americans, often experience delays in diagnosis, decreased adherence to treatment guidelines, and poorer outcomes compared to their urban counterparts due to these geographic barriers.15,16 Moreover, the long travel distances required to access cancer care can result in additional financial burdens for Native American patients, who may face difficulties securing transportation and accommodations, as well as lost wages due to the time spent traveling to and from treatment centers.17 These factors can further exacerbate existing socio-economic disparities and contribute to reduced access to quality cancer care.
Efforts to address these geographic barriers include expanding telemedicine services for remote consultations and follow-up care,18 as well as investing in the development of regional cancer care facilities and transportation infrastructure to improve access to NCI-designated cancer centers for Native American populations.19 Despite the well-documented disparities in cancer outcomes and healthcare access for Native Americans, there is a notable lack of research specifically addressing disparities in accessibility to high-quality cancer care centers, such as NCI-designated cancer centers, for this population.20 Existing research has primarily focused on cancer incidence, mortality, and screening rates, while the impact of geographic barriers on access to specialized cancer care centers remains understudied.21
Understanding the extent of these disparities is essential for informing targeted interventions aimed at reducing barriers to cancer care and improving health outcomes for Native American communities.22 Comprehensive evaluations of accessibility, including travel distance, travel time, and other factors affecting access to NCI-designated cancer centers, can help identify specific challenges faced by Native American cancer patients and guide the development of effective solutions.23 Furthermore, research on disparities in accessibility should also account for socioeconomic, cultural, and historical factors that may contribute to the observed disparities in cancer care access and outcomes for Native Americans.24 This holistic approach is critical for identifying the underlying causes of these disparities and designing interventions that address the unique needs of Native American populations.25
There is a pressing need for research that specifically investigates disparities in accessibility to NCI-designated cancer centers among Native American cancer patients. This research can inform targeted interventions and policy changes aimed at reducing barriers to cancer care and ultimately improving cancer outcomes for this vulnerable population.
Methods
Retrospective Collection of Geographic Information
This retrospective study was approved by the institutional review board at the University of Utah. For the study, informed consent was waived due to the use of retrospective data. The study fully complied with the US patient confidentiality regulations, including adherence to the Health Insurance Portability and Accountability Act of 1996. Eligible patients were identified from the electronic medical records. Patients diagnosed with genitourinary cancer were reviewed from February 1, 2013, to January 31, 2023. Clinical data, including age, gender, smoking history, obesity, history of surgery, metastatic sites, and demographic data such as race, education level, employment status, and home address, were collected and compared between the two cohorts (Native American vs. white).
Mapping of Hematologist and Oncologist Clinics and NCI-Designated Cancer Centers
Practice sites throughout the US with at least one hematologist or medical oncologist actively billing for Medicare in the prior year were recorded. The point map using publicly available data from Medicare Care Compare (https://www.cms.gov/medicare) was created. The shapefile containing information on NCI-designated cancer centers was downloaded from the NCI website.26
Calculation of Travel Distance
The travel distance from patients' home zip code to Huntsman Cancer Institute (HCI) at the University of Utah was calculated using GeoData ZIP Code Distance Calculations Matrix Template.27 This method provides an accurate estimate of the distance patients need to travel to access specialized cancer care at HCI, allowing for a comparison of travel distances between Native American and white cancer patients. To provide a nationally representative control group, Area Deprivation Index (ADI) matched block groups from the 2020 census were utilized.28 The top ten most populated native American reservations were analyzed. ADI state decile was used to match between Native American reservations and the control block groups within the same state, resulting in 1,146 matched block groups.29 The travel distance of the 1,146 matched block groups to the nearest NCI-designated cancer center was calculated and compared to the Native American group. Travel time was also calculated using Google Maps to provide additional context for the accessibility challenges faced by these populations.30
Data Visualization
Locations were mapped in ArcGIS 10.7 using coordinates and a 5-digit zip code tabulation area (ZCTA).31 This visualization tool allows for the clear representation of geographic disparities in accessibility to NCI-designated cancer centers, as well as the identification of specific areas where interventions may be most effective in addressing these disparities.
Statistical Analysis
The collected data was analyzed using the R software package. Statistical comparisons between groups were made using paired student t-tests for continuous variables and chi-square tests for categorical variables. A p-value of less than 0.05 was considered statistically significant for all tests after the adjustment. Results are reported as mean ± standard deviation (SD) for continuous variables and frequencies for categorical variables.
Results
Comparison of Median Travel Distance for Native American and White Patients to HCI
During the ten-year period, a total of 468 Native American patients were seen at our cancer clinic for genitourinary cancers, of whom 56.6% (n = 265) were women. The median age was 58 years old (range 15 – 97). These patients were 1:5 matched by age and tumor sites with a cohort of white patients (n = 2340), to determine disparities in travel distance and accessibility to cancer care at HCI. The median travel distance for Native American patients to HCI was found to be 190.6 miles (range 1.1 – 596.4 miles), significantly greater than the median travel distance for white patients, which was 21.6 miles (range 1.1 – 269 miles) (p < 0.0001) (Supplementary Figure 1).
Travel Distance from Native American Reservations to NCI-Designated Cancer Centers
Based on the US 2010 census, the top ten most populated native American reservations were analyzed. The total population was 267,687 (Figure 1).
In the continental US, the median travel distance from Native American reservations to the nearest NCI-designated cancer centers was 186.5 miles (range 77.8 – 629 miles), compared to 159 miles (range 1.9 – 671.3 miles) for ADI-matched block groups (p < 0.001) (Table 1). The observed disparities in travel distances for both comparisons were statistically significant, indicating a substantial difference in accessibility to NCI-designated cancer centers for Native American patients compared to their white counterparts and the general population represented by ADI-matched block groups.
Figure 1. NCI-designated cancer center sites and Native American reservations
Table 1. Comparison of travel distance to NCI cancer centers between Native American reservations and ADI-matched block groups. Abbreviations: ADI, Area Deprivation Index; NCI, National Cancer Institute; SD, standard deviation.
| Travel distance to nearest NCI-designated cancer center | p value | ||
|---|---|---|---|
| Native American reservations | ADI-matched block groups (mean+/- SD) | ||
| Navajo Nation (NM) | 202 miles | 133 +/- 54.9 miles | <0.0001 |
| Pine Ridge Reservation (SD) | 339 miles | 301.8 +/- 83.7 miles | <0.0001 |
| Fort Apache Reservation (AZ) | 171 miles | 102.1 +/- 66.6 miles | <0.0001 |
| Gila River Indian Reservation (AZ) | 86.4 miles | 101 +/- 58.1 miles | 0.01 |
| Osage Reservation (OK) | 130 miles | 91 +/- 41.6 miles | <0.0001 |
| San Carlos Reservation (AZ) | 141 miles | 101 +/- 58.1 miles | <0.0001 |
| Rosebud Indian Reservation (SD) | 391 miles | 301.8 +/- 83.7 miles | <0.0001 |
| Tohono O'odham Nation Reservation (AZ) | 77.8 miles | 102.1 +/- 66.6 miles | 0.0003 |
| Blackfeet Indian Reservation (MT) | 629 miles | 482.9 +/- 76.4 miles | <0.0001 |
| Flathead Reservation (MT) | 477 miles | 441.7 +/- 85.1 miles | 0.0008 |
Travel Time from Native American Reservations to Cancer Care
Among a total of 267,687 population, there were 33 hematologists/oncologists at the nearest clinic. Visual representation provides the locations of Native American reservations across the continental US and its distance to the nearest hematologists and oncologists (Figure 2).
Supplementary Table 1 shows the travel time from Native American reservations to cancer care. As expected, the nearest hematologist/oncologist sites were closer to Native American reservations than NCI-designated cancer centers. The median travel distance from the Native American reservations to their nearest hematologist/oncologist was 90.4 miles (range 24.9 – 207 miles), and the median travel time was 1 hr 46 min. The median travel distance from the Native American reservations to their nearest NCI cancer center was 186.5 miles (range 77.8 – 629 miles), and the median travel time was 3 hr 26 min.
Figure 2. Cancer clinic sites and Native American reservations
Discussion
Our study revealed a significant disparity in travel distance for Native American cancer patients in Utah seeking treatment at the Huntsman Cancer Institute compared to their white counterparts. Native American patients were found to travel a median distance of 190.6 miles, while white patients traveled a median distance of 21.6 miles (p < 0.0001). This finding is consistent with previous studies that have identified travel distance as a potential barrier to accessing healthcare for Native American populations, particularly for those residing in rural areas or on reservations.23,32 The increased travel distance for Native American patients may have implications for timely diagnosis and treatment, as well as for overall patient outcomes and satisfaction.
Our analysis of the ten most populated Native American reservations in the United States showed that the median travel distance from these reservations to the nearest NCI-designated cancer centers was significantly longer compared to ADI-matched block groups (186.5 miles vs. 159 miles, p < 0.001). This finding suggests that Native American patients living on reservations face additional geographic barriers when seeking specialized cancer care at NCI-designated cancer centers.
Moreover, NCI-designated cancer centers are known for providing state-of-the-art cancer treatments, cutting-edge research opportunities, and multidisciplinary care teams that can significantly improve patient outcomes.33 Therefore, the limited accessibility of these centers for Native American populations could contribute to existing disparities in cancer care and outcomes.
Geographic barriers to accessing cancer care have been shown to contribute to health disparities among racial and ethnic minorities.34 In the case of Native American populations, these barriers may exacerbate existing disparities in cancer incidence, mortality, and access to care.6,35 The longer travel distances to NCI-designated cancer centers for Native American patients may result in delayed or inadequate treatment, increased financial burden, and reduced quality of life.36,37 Furthermore, previous studies have shown that increased travel distance correlated with worse survival outcomes in multiple cancer settings, supporting the need for healthcare policies aimed at mitigating the disparities encountered by the NA population in the US.38-39,40
Our study could not capture the data of NA cancer patients who opted not to visit a hospital. Future research should further explore the impact of these geographic barriers on the cancer care experience and outcomes of Native American patients, as well as potential interventions to address these disparities. Possible strategies to improve access to care for Native American populations may include telemedicine, mobile clinics, and the development of partnerships between NCI-designated cancer centers and tribal health programs.
Conclusion
The travel distance to NCI-designated cancer center for NA cancer patients in Utah was around nine times longer than that of white cancer patients. This study highlights the significant disparity in cancer care accessibility faced by NA communities and the need for healthcare policies to mitigate these disparities.
Conflicts of Interest
Neeraj Agarwal, MD: has received honorarium before May 2021 and during his lifetime for consulting to Astellas, AstraZeneca, Aveo, Bayer, Bristol Myers Squibb, Calithera, Clovis, Eisai, Eli Lilly, EMD Serono, Exelixis, Foundation Medicine, Genentech, Gilead, Janssen, Merck, MEI Pharma, Nektar, Novartis, Pfizer, Pharmacyclics, and Seattle Genetics; and has received research funding during his lifetime (to NA's institution) from Arnivas, Astellas, AstraZeneca, Bavarian Nordic, Bayer, Bristol Meyers Squibb, Calithera, Celldex, Clovis, CRISPR Therapeutics, Eisai, Eli Lilly, EMD Serono, Exelixis, Genentech, Gilead, Glaxo Smith Kline, Immunomedics, Janssen, Lava, Medivation, Merck, Nektar, Neoleukin, New Link Genetics, Novartis, Oric, Pfizer, Prometheus, Rexahn, Roche, Sanofi, Seattle Genetics, Takeda, and Tracon.
Umang Swami, MD: has been paid for a consulting or advisory role by Seattle Genetics, Astellas Pharma, Exelixis, Imvax, and AstraZeneca, currently or during the past 2 years. Dr. Swami's institution has received research funding from Janssen, Seattle Genetics/Astellas, and Exelixis, currently or within the past 2 years.
Benjamin L. Maughan, MD, PharmD: Consultancy to Roche/Genentech, Pfizer, AVEO Oncology, Janssen Oncology, Astellas, Bristol-Myers Squibb, Clovis, Tempu, Merck, Exelixis, Bayer Oncology, Peloton Therapeutics (C/A), Exelixis, Bavarian-Nordic, Clovis, Genentech, Bristol-Myers Squibb (FR– institutional).
Funding Information
N/A
Ethical Statements
N/A
Informed Consent
N/A
Data Availability Statement
The data that support the findings of this study are available from the corresponding author upon reasonable request.
Code availability (software application or custom code): The code that supports the findings of this study is available from the corresponding author upon reasonable request.
Acknowledgements
Research reported in this publication utilized biostatistics resources at Huntsman Cancer Institute at the University of Utah and was supported by the National Cancer Institute of the National Institutes of Health under Award Number P30CA042014. The content is solely the responsibility of the authors and does not necessarily represent the official views of the NIH.
Declaration of AI Use in Scientific Writing
N/A
Author Contributions
Concept and design: HL, GG, KKS, US, BLM, NA, YJ
Data acquisition: HL, GG, KKS
Data analysis and interpretation: HL, XL, KKS, US, NA
Drafting of the manuscript: HL, GG, CHC, KKS, US, BLM, NA
Critical revision of the manuscript: HL, GG, CHC, KKS, XL, US, BLM, NA, YJ
All authors (HL, XL, GG, YJ, NA, KKS, BLM, US, CHC) approved the final version of the manuscript and agree to be accountable
Supplementary Material
Supplementary Tables
Supplementary Table 1. Travel time from Native American reservations to cancer care. Abbreviations: NCI, National Cancer Institute.
| Nearest hematologist oncologist sites | Nearest NCI cancer center | |||||
|---|---|---|---|---|---|---|
| Site | Travel distance | Travel time | Site | Travel distance | Travel time | |
| Navajo Nation (Ariz.-N.M.-Utah) | Tuba City Regional Health Care Corporation | 187 miles | 3 hr 31 min | University of New Mexico Comprehensive Cancer Center | 202 miles | 3 hr 29 min |
| Pine Ridge Reservation (S.D.-Nebr.) | Regional West Medical Center | 138 miles | 2 hr 31 min | University of Colorado Cancer Center | 339 miles | 5 hr 44 min |
| Fort Apache Reservation (Ariz.) | Summit Healthcare Association | 34.8 miles | 47 min | Arizona Cancer Center at University of Arizona | 171 miles | 3 hr 22 min |
| Gila River Indian Reservation (Ariz.) | Ironwood Cancer & Research Centers | 42.3 miles | 41 min | Arizona Cancer Center at University of Arizona | 86.4 miles | 1 hr 19 min |
| Osage Reservation (Okla.) | Oklahoma Cancer Specialists and Research Institute (OCSRI)/Tulsa Cancer Institute | 62.3 miles | 1 hr 7 min | Stephenson Cancer Center at University of Oklahoma | 130 miles | 2 hr 16 min |
| San Carlos Reservation (Ariz.) | San Carlos Apache Healthcare Corporation (SCAHC) | 24.9 miles | 31 min | Arizona Cancer Center at University of Arizona | 141 miles | 2 hr 42 min |
| Rosebud Indian Reservation and Off-Reservation Trust Land (S.D.) | Great Plains Health/Callahan Cancer Center | 207 miles | 3 hr 29 min | Fred & Pamela Buffett Cancer Center at Nebraska Medicine & the University of Nebraska Medical Center | 391 miles | 5 hr 41 min |
| Tohono O'odham Nation Reservation and Off-Reservation Trust Land (Ariz.) | Ironwood Cancer & Research Centers | 135 miles | 2 hr 15 min | Arizona Cancer Center at University of Arizona | 77.8 miles | 1 hr 31 min |
| Blackfeet Indian Reservation and Off-Reservation Trust Land (Mont.) | Kalispell Regional Medical Center | 111 miles | 2 hr 9 min | Fred Hutchinson/ University of Washington Cancer Consortium | 629 miles | 10 hr 25 min |
| Flathead Reservation (Mont.) | RCHP Billings - Missoula | 69.7 miles | 1 hr 23 min | Fred Hutchinson/ University of Washington Cancer Consortium | 477 miles | 7 hr 48 min |
Supplementary Figures
Supplementary Figure 1. The home locations of Native American patients in Utah
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