Racial and Ethnic Disparities in Cancer Occurrence and Outcomes in Rural United States: A Scoping Review

Abstract

Background

Cancer is the second-leading cause of death in the United States. Most studies have reported rural versus urban and Black versus White cancer disparities. However, few studies have investigated racial disparities in rural areas.

Objective

We conducted a literature review to explore the current state of knowledge on racial and ethnic disparities in cancer attitudes, knowledge, occurrence, and outcomes in rural United States.

Methods

A systematic search of PubMed and Embase was performed. Peer-reviewed articles published in English from 2004-2023 were included. Three authors independently reviewed the articles and reached a consensus.

Results

After reviewing 993 articles, a total of 30 articles met the inclusion criteria and were included in the present review. Studies revealed that underrepresented racial and ethnic groups in rural areas were more likely to have low cancer-related knowledge, low screening, high incidence, less access to treatment, and high mortality compared to their White counterparts.

Conclusion

Underrepresented racial and ethnic groups in rural areas experienced a high burden of cancer. Improving social determinants of health may help reduce cancer disparities and promote health.

Keywords

cancer health disparities rural race ethnicity

Introduction

Cancer, or the collection of diseases caused by the body’s uncontrolled division of cells, is the second-leading cause of death in the United States (U.S.), exceeded only by heart disease.^1,2 In 2023, there were an estimated 2 million cancer diagnoses and over 609,000 cancer deaths in the U.S.³ According to the 2022 U.S. Census Bureau, more than 46 million, or about 15% of the U.S. population, live in rural areas.⁴ United States Department of Agriculture (USDA), Economic Research Service (ERS) researchers develop “rural” classifications on the basis of counties, with nonmetro countries including some combination of open countryside and a fewer number of people and housing units.⁵ While cancer death rates have decreased nationwide, there is a slower reduction in cancer death rates in U.S. rural areas, driven partly by high death rates from colorectal, prostate, lung, and cervical cancers.⁶

Most cancer research has highlighted either rural versus urban disparities or racial disparities separately.^7-12 When rural underrepresented populations were included, they were compared with urban underrepresented populations while rural Whites were compared with urban Whites.^13-15 In general, rural populations experienced a higher burden of cancer than urban populations, and underrepresented racial and ethnic groups more than their White counterparts. Those individual disparities could result in racial and ethnic disparities in rural areas with an additional burden on underrepresented populations living in the rural United States. Few studies, however, have focused on racial disparities related to the intersection of race and rurality.¹⁶

Rural communities in the United States are becoming more populated and increasingly diverse.¹⁷ Understanding cancer disparities in rural areas will help design appropriate public health interventions to reduce cancer and promote health. This scoping review aimed to comprehensively review the literature and summarize the current knowledge on racial and ethnic disparities in cancer occurrence and outcomes in rural United States.

Methods

Protocol

The protocol was registered with IMPLASY (INPLASY202450041) and the review was conducted based on the Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement.¹⁸

Search Strategy

A systematic search of Medline (PubMed) and Embase (Ovid) databases was performed using keywords and Medical Subject Headings (MeSH) terms for “cancer”, “disparities”, “differences”, “inequalities”, “race”, “rural” and “United States.” A hand search of the relevant articles’ reference lists and reviews was also performed. The search was restricted to the past 20 years (2004-2023).

Inclusion/Exclusion Criteria

We included (1) qualitative and quantitative studies, (2) conducted in rural areas of the U.S. and comparing race and/or ethnicity groups, involving (3) adult population (age >18 years), (4) published in English, (5) in a peer-reviewed journal. Rural areas included areas with a small population density, size or notable distance to a metropolitan/urban area.¹⁹ We excluded (1) articles that were a review, commentary, or expert opinion, (2) duplicate studies or overlapping data, and (3) articles without full-text or abstract-only papers.

Screening and Data Extraction

Three reviewers independently screened the articles and extracted the relevant information according to the PRISMA guidelines. Any disagreements were resolved via discussion to reach a consensus. The following information was extracted: the study details (title, location, publication journal, and year); study characteristics (design, participants, sample size, and type of analysis); type of cancer and outcome, covariate-adjusted for, measures of effect, findings, and limitation.

Outcome: several outcomes were assessed including cancer knowledge and attitude, screening, incidence, treatment, survival, and mortality.

Comparison: underrepresented racial and ethnic groups were compared to non-Hispanic Whites.

Data Synthesis and Analysis

A narrative synthesis was performed due to the limited number and heterogeneity of the included studies.

Results

The search yielded 993 articles that were screened and 30 met the inclusion criteria of this review (Figure 1). All studies were conducted in the U.S, the majority in the southern states with Georgia (5 studies), Alabama (4 studies), and North Carolina (4 studies) being the states the most represented (Figure 2). Quantitative studies represented 87.1 % of the included studies while the remaining 12.9% were qualitative studies. The cancers the most studied were breast (6 studies) and colorectal (6 studies) cancers.

Figure 1.

PRISMA flowchart.

Figure 2.

Description of included studies by location (a), design (b), outcome (c), and type of cancer (d).

Knowledge and Attitude

Paskett and colleagues surveyed 897 women aged >40 years in rural North Carolina (i.e., Robeson County) to assess their cancer knowledge and attitude.²⁰ Overall, their findings revealed that 43% and 53% did not mention mammograms and Pap smears as breast and cervical carcinoma screening tests, respectively. Most importantly, they found in this rural population, that Blacks and Native American women were less likely to mention these screening tests compared with White women (p < .001). In addition, rural Black women were less likely to have ever been encouraged to receive a mammogram compared to their White (48% vs 62%; p = .002) and Native American women counterparts (48% vs 56%; p = .070). In most cases, the encouragement originated from a physician, a family member, or a friend.²⁰

In another cross-sectional study of 138 participants conducted also in rural North Carolina (Person County), Cates and colleagues reported that Black respondents were less likely to have heard of Human papillomavirus (HPV) (24% vs 57%, p < .001) compared to White respondents.²¹ Furthermore, Blacks had lower HPV knowledge (29% vs 42% correct responses, p < .05), and were less likely to think that cervical cancer would be a serious health threat (75% vs 96%, p < .001) than Whites respondents.²¹

In a qualitative study conducted in rural Alabama, Black breast cancer survivors expressed a need for social support from family, friends, and health care providers. They experienced fear of rejection related to cancer and were therefore unwilling to share their cancer diagnosis, to protect their family and friends.²² Issues related to breast cancer quality-of-life such as lymphedema, body image, and sexuality were misunderstood. They relied on spirituality and religion as essential sources of coping with and accepting their cancer diagnosis.²² Similar concerns were raised about prostate cancer in another study conducted in rural West Central Alabama.²³ The author identified 6 common themes related to prostate cancer attitudes and beliefs in Black men including disparity, lack of understanding, tradition, mistrust in the system, fear, and threat to manhood.²³

Public health intervention programs could, however, help increase cancer knowledge. Several studies have identified areas of potential interventions. A study conducted in rural New Mexico found that Hispanic women were more interested in receiving breast cancer cell phone messages than non-Hispanic women (67 vs 27%).²⁴ A more recent study published the results from the Colorectal Cancer Outreach and Screening Initiative to Promote Awareness and Knowledge of Colorectal Cancer in Racial/Ethnic and Rural Populations.²⁵ The post-educational activity survey revealed an increase in colorectal cancer-related knowledge. Participants strongly agreed that the educational event increased the likelihood that they would engage in colorectal cancer-related healthful behaviors such as obtaining colorectal cancer screening and increasing physical activity.

Screening

Rural minorities may face different barriers to colorectal cancer screening than rural non-Hispanic Whites as suggested by lower screening.²⁶ In Georgia for example (i.e., McDuffie and Screven counties), a study reported that Blacks had lower colorectal cancer screening rates (50.4%) and were more likely to report barriers to screening than Whites (63.4%; p = .009).²⁷ Barriers to screening were also observed for oral cancer among rural Black Americans in Florida.^28,29 Those barriers included low knowledge/social attention, lack of resources, and fear of screening and diagnosis, with lack of resources emerging as the largest barrier.

Another study involving Black rural residents from North Carolina noted the importance of patient-health care providers’ communication in colorectal cancer control.³⁰ Those who self-rated their communication with their health care provider as good were nearly 3 times more likely to have been screened within the recommended guidelines than those with poor communication (OR = 2.8, 1.2-6.4). Similarly, those with adequate cancer knowledge were more likely to have completed colorectal cancer screening.³⁰

In contrast, a study conducted in rural Washington State did not find an ethnic disparity among rural Whites. When comparing rural Hispanic Whites to rural non-Hispanic Whites, Ducan and colleagues reported similar rate of receiving a mammogram according to the guidelines.³¹

A public health intervention through of a quasi-experimental study among Black women conducted in rural Alabama consisting of group educational sessions and an in-home visit was effective in improving mammography attainment (38% increase from baseline).³² In addition, the intervention resulted in a reduction in barriers to mammography attainment.

Incidence

A study conducted in South Carolina revealed that the incidence of colorectal cancer was constantly higher in rural Blacks from 1996 to 2016 than in rural Whites.³³ Both groups experienced a decline in colorectal cancer incidence but the gap between rural Blacks and rural Whites persisted over time.

In rural Georgia, Black residents had the highest colorectal cancer incidence for early onset of colorectal cancer (age 40-49) and even after 50 years.³⁴ The disparity between Blacks and Whites was more pronounced with Black rural residents experiencing more colorectal cancer compared to their White counterparts (p < .003).³⁴

Treatment

Access to Treatment

In their study involving Medicare beneficiaries in the first 12 months after diagnosis of breast, lung, colorectal, or prostate cancer, Onega and colleagues noticed disparities in access to specialized cancer care.³⁵ They found that rural Black patients were 58% less likely to attend a specialized cancer center than rural White patients (OR = 0.42; 95% CI: 0.26-0.66).³⁵

In their ecological study, LaVigne and colleagues found that areas with more oncologic needs were disproportionately rural communities with a higher percentage of Black non-Hispanic constituents and a higher percentage of poverty.³⁶ A study involving newly diagnosed prostate cancer patients in rural Southwest Georgia revealed that Black men were almost 4 times more likely to choose treatment other than surgery compared to White men (OR = 3.51, 95% CI: 1.92-6.41).³⁷ The authors suggested that this disparity may be caused more by income difference than race (as race was no longer significant when adjusted for income). In addition, Black participants reported more poor communication with their physician than White participants (OR = 3.95, 95% CI: 1.52-10.30).³⁷

Chemotherapy

Among patients diagnosed with breast cancer in rural South Carolina, Black women were twice as likely to receive late chemotherapy compared to White women (OR = 2.0, CI: 1.1-3.7).³⁸ However, another study conducted in southwest Georgia indicated that Black breast cancer patients received or completed chemotherapy at rates that equal or exceeded White patients.³⁹ A difference between Blacks and Whites was only noticed among patients who were not married, highlighting the importance of social support.

Receipt of Surgery

In another study involving 3481 Medicare beneficiaries in Alabama, Blacks in rural counties were 67% less likely to undergo surgery for lung cancer than their White counterparts (OR = 0.33, 95% CI: 0.19-0.57).⁴⁰ This significant result was obtained after controlling for age at diagnosis, gender, stage at diagnosis, comorbidity score, and socioeconomic status.

Radiation

A study found that travel distance to radiation therapy facilities in rural areas majority populated with American Indian/Alaska Native (AI/AN) was on average 58.4 miles (95% CI: 31.6, 67.4) longer than rural areas majority populated with Whites.⁴¹ In Washington State, among decedents with cancers likely requiring radiotherapy, non-Hispanic American Indians and Alaska Natives decedents in rural areas would have had to travel 1.39 times (95% CI: 1.22-1.58) farther from their residences to reach the nearest treatment facility compared to their White counterparts.⁴²

Survival

A study published in JAMA Open found that the 5-year survival of the most common cancers in rural areas (lung, prostate, breast, and colorectal cancers) was shorter in rural non-Hispanic Black patients.⁴³ In this large cohort, from 1975 to 2016, the 5-year lung cancer survival rate in Black rural patients, for example, slightly improved from 55.1 % to 57.7%, but was still the shortest among all cancer types and races.⁴³ However, another study involving 934 non-small cell lung cancer patients in Southwest Georgia did not find such evidence of racial disparities in survival.⁴⁴

That was not the case for head and neck cancer. In the study by Clarke and colleagues, the median survival time of head and neck cancer for Whites was 59.1 months (57.2-60.0) and 35.1 months (31.9-39.0) for Blacks in rural areas.⁴⁵ Compared to White rural, they found that Black rural patients were 17% less likely to survive (HR = 1.17; 95% CI: 1.15-1.19).

Mortality

Ecological studies have been used to identify areas and populations most affected by cancer mortality. The highest mortality rates were observed among Black residents of rural counties with persistent poverty for all sites and more specifically colorectal, oropharyngeal, breast, cervical, and prostate cancers.⁴⁶ Furthermore, counties with high incidence and death rates of prostate and breast cancer were largely rural, generally with a higher percentage of Black non-Hispanic constituents.³⁶

In Georgia, cancer mortality hot spots were heavily concentrated in rural areas (i.e., eastern Piedmont to Coastal Plain regions, southwestern rural Georgia, and northern-most rural Georgia). Those areas generally had a higher proportion of Black, older adults, and higher poverty.⁴⁷

In South Carolina, colorectal cancer mortality was higher in rural Blacks than rural Whites from 1996 to 2016. Both groups experienced a decline but the gap between Blacks and Whites has persisted.³³ Nationwide, compared to White rural, Black rural patients had a 25% higher risk of head and neck cancer mortality (HR = 1.25, 95% CI:1.15-1.19).⁴⁵ Brooks and colleagues found Blacks in rural areas had a 24% increased risk of prostate cancer mortality than their white counterparts, but that difference was not statistically significant (OR = 1.24, 95% CI: 0.90-1.70).⁴⁸

Discussion

This review revealed racial and ethnic disparities in cancer-related knowledge and attitudes, screening, incidence, treatment access and need, and mortality in rural United States. Underrepresented ethnic and racial groups in rural areas experienced lower cancer knowledge, lower screening attainment, higher incidence, mortality, and more challenges accessing cancer treatment than non-Hispanic Whites living in rural United States. Previous studies have noticed racial disparities in cancer occurrence and outcomes in similar geographic areas. For example, a study found that in the Mississippi Delta Region of the U.S., a mostly rural area, Blacks had higher cancer mortality than Whites for all cancer types except lung cancer.⁴⁹ Similar findings have been reported in mostly rural areas in Louisiana known as the “Cancer Alley” and California.^50,51

Multiple reasons could explain these racial disparities in rural areas. First, social determinants of health may play an essential role. In addition to living in rural areas, having low income, low educational attainment, reduced access to health care services, being under- or uninsured, and social isolation can worsen cancer health disparities.⁵² Studies have demonstrated that underrepresented ethnic and racial groups experience more unfavorable social determinants of health compared to Whites.⁵³ Furthermore, some models revealed a reduction or elimination of cancer racial disparities when controlling for social determinants of health such as income and social support indicating their contribution to the observed disparities.^37,39 Therefore, there is a need to address social determinants of health, specifically in underserved rural populations.^10,54

Environmental factors may also explain racial disparities in cancer in rural areas. Historical and environmental racism have impacted underrepresented racial and ethnic groups and have led to inequitable exposure to environmental pollutants. For instance, the area called “Cancer Alley” is a long stretch of petrochemical exposures between Baton Rouge and New Orleans, in a largely rural and mostly Black populated area.^50,55 In addition, research has shown that systemic racism in the form of residential segregation contributed to increased diagnoses of breast cancer, for example, and poorer prognoses among Black women born in the Jim Crow era.⁵⁶

Cultural factors may also play a role in racial and ethnic disparities in cancer outcomes. As revealed by several studies, distrust in the health care system is common in underrepresented racial and ethnic groups in rural areas.²³ More effort should be placed in improving trust in the health care system. It has been also suggested that social bonds could promote stronger or more effective interpersonal support to facilitate higher screening rates for cancers.^46,57

This review was limited by the paucity of studies that explored racial disparities in rural areas. Further research is needed, specifically in rural areas other than the Southern United States, in cancer incidence, involving other various types of cancer and studies design to better understand cancer disparities experienced by racial and ethnic underrepresented populations. More effort is needed to develop appropriate policies that address health disparities and promote health equity.

Conclusion

Cancer disparities disproportionally affect underrepresented racial and ethnic groups in rural United States. Improving social determinants of health such as access to high-quality education and income stability among rural underserved communities could help mitigate cancer disparities. Improved access to cancer knowledge, screening, and specialized care should be an integral part of reducing cancer disparities in rural settings. Culturally tailored interventions may also help reduce the cancer burden.

Footnotes

Declaration of Conflicting Interests

The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Funding

The author(s) received no financial support for the research, authorship, and/or publication of this article.

Ethical Statement

ORCID iD

Anuli Njoku

Data Availability Statement

The raw data that support the findings of this study are available on request from the corresponding author.*

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