This structured scoping review followed the Arksey and O-Malley framework and was reported in accordance with the PRISMA-ScR guidelines. The objective was to map the breadth of literature examining cancer inequities faced by displaced and migrant populations along the U.S.-Mexico border region, with emphasis on surveillance limitations, access barriers, and structural determinants.

For this review, “displaced and migrant populations” were operationally defined as individuals residing in, transitioning through, or receiving care within the U.S.-Mexico border region who experience mobility, legal precarity, cross-border healthcare utilization, or migration-linked structural vulnerability. This included undocumented migrants, asylum seekers or forcibly displaced persons, seasonal and agricultural workers, cross-border patients receiving care in both countries, and hispanic residents of border counties experiencing migration-linked barriers. Studies focusing solely on nationally representative Hispanic populations without border-region stratification were categorized as contextual rather than border-specific.

A comprehensive search strategy was developed using medical subject heading (MeSH) terms and terms used in prior migrant-health systematic reviews. Databases searched included PubMed/Medline, Scopus and ScienceDirect. Gray literature was identified from the Centers for Disease Control and Prevention (CDC), U.S. Customs and Border protection (CBP), U.S.-Mexico Border Health Commission and the U.S. Department of Health and Human Services. Searches covered January 1, 2010 through April 30, 2024 (Tables 1,2).

Search strategies were adapted for each database. The PubMed search string was:

(“cancer”[MeSH Terms] OR cancer* OR oncology OR malignant*) AND (“migrant*” OR “immigrant*” OR “refugee*” OR “displaced” OR “undocumented” OR “foreign-born”) AND (“U.S.-Mexico border” OR “US-Mexico border” OR “Mexico-U.S. border” OR “border health” OR “Texas border counties”) AND (“disparity*” OR “inequity*” OR “access” OR “screening” OR “epidemiology*” OR “registry”) Filters: English, 2010–2024.

Government and policy websites were searched using combinations of “cancer”, “border health”, “U.S.-Mexico border”, “migrant health”, “registry”, and “surveillance”.

Studies were included if they met all of the following:

Published between January 2010 and April 2024.

Eligible study designs included observational quantitative studies, qualitative studies, mixed-methods studies, government or institutional public health reports and policy analyses directly related to border-region cancer epidemiology.

Were published prior to 2010.

Media articles and historical reports prior to 2010 were excluded from the formal synthesis but may be referenced contextually in the discussion.

The database and gray literature search yielded 336 records. After removal of 160 duplicates, 176 records underwent title/abstract screening. 100 articles were excluded due to non-eligible population, setting, or lack of cancer-specific outcomes. Full-text articles were reviewed for the remaining 76 articles. A total of 12 full-text articles met all inclusion criteria and were included in the final synthesis.

The included sources represented a mix of quantitative observational studies and border-relevant institutional/governmental reports. Most studies focused on Hispanic border residents, cross-border patients, and migrant populations experiencing structural vulnerability in U.S. border counties and adjacent Northern Mexican regions. The focus on cancer types and themes spanned cervical cancer screening, hematologic malignancies, infection-associated cancers, health system capacity and surveillance infrastructure.

Across included studies, study populations were predominantly Hispanic residents of Texas border counties and cross-border patients receiving care in both the United States and Mexico [1, 2, 6]. Migrant populations traversing the northern Mexican border were characterized by high mobility, limited continuity of care, and inconsistent access to preventive services [7]. Although displaced and migrant populations were consistently described as structurally vulnerable, documentation status and forced displacement were rarely measured directly. Most studies relied on geographic residence, cross-border utilization patterns, or ethnicity-based proxies [8].

Barriers to screening and early detection were most commonly linked to insurance and affordability constraints and to limited screening capacity in border health systems (Figure 2). Among Hispanic women in the border region, breast cancer screening was reported at 56% compared with 72% among non-Hispanic white women nationally [9]. Cervical cancer screening rates among women aged 21–65 in certain Texas border counties were reported as low as 52% [10]. HPV vaccination completion represented an additional preventive gap, with only 44% of Hispanic women completing the vaccine series compared with 62% of non-Hispanic women [11]. These disparities were reported alongside high uninsured rates, which exceed 30% in some border counties [1].

Promotora -led interventions were associated with improved screening adherence among previously non-compliant women, with more than 75% completing pap smear screening following outreach [9]. Mobility further disrupted continuity of screening among migrants lacking records and consistent access to preventive services [7].

Border-region healthcare infrastructure constraints were consistently reported, including workforce shortages and limited oncology specialty access. In some Texas border counties, the primary care physician-to-population ratio was approximately 1 per 1,957 residents compared with a national average of about 1 per 1,320 [12]. Multiple sources described limited specialist availability and delayed diagnostic pathways, with prolonged time (more than 90 days) from symptom onset to diagnosis reported in border communities [13]. Constraints in screening equipment availability were also noted in high-need counties. For example, Hidalgo County has one mammogram machine per 26,000 women over 40 years old [10]. Furthermore, the lack of bilingual staff and language discordance within clinical encounters was described as contributing to delayed care and fragmented communication [14].

Environmental and occupational exposures were recurrently discussed as potential contributors to cancer risk in border communities, particularly air pollution and pesticide exposure. El Paso and Laredo ranked among the highest Texas regions for ozone and PM2.5 exposure levels [8]. Respiratory assessments in border populations have documented elevated asthma prevalence associated with air pollution exposure [16]. Additionally, water contamination was reported in more than 20% of sampled sites, with elevated nitrate levels associated with gastrointestinal cancer risk [17]. Occupational pesticide exposure among migrant and agricultural workers was associated with a 2.6-fold increased risk of hematologic malignancies [18]. A case series in Texas also reported pediatric poisonings from agricultural pesticide exposure [19].

Among maquiladora workers in northern Mexico, prolonged solvent exposure has been associated with increased bladder and liver cancer incidence. Food insecurity was also reported as prevalent in some border households (32%), representing a structural determinant potentially associated with obesity-related cancer risk [20]. Although these exposures were consistently identified, quantification varied substantially across sources.

Undocumented individuals and structurally vulnerable migrants were frequently represented in institutional and policy analyses examining chronic disease burden and access barriers in the border region [21]. Seasonal and agricultural workers were identified as a high-risk subgroup due to occupational carcinogen exposure and reduced healthcare engagement [18].

Clinical research participation barriers were described in terms of underrepresentation, limited research infrastructure, and mistrust. Only 3% of cancer clinical trial participants in the U.S. identify as Hispanic, despite Hispanics comprising 19% of the national population [22]. It was reported that low participation rates were attributed in part to limited research infrastructure and bilingual recruitment efforts [23]. In a qualitative study, Mexican-American respondents cited fear of experimentation, lack of understanding, and transportation difficulties as key deterrents to clinical trial participation [14]. A recent policy analysis also noted that funding for border-region clinical research is 5 times lower per capita than in urban U.S. regions [23].

Migration across the U.S.–Mexico border reached 2.475 million encounters in fiscal year 2023 compared with 977,000 in fiscal year 2019 [3]. This surge was reported to place additional strain on already resource-limited border clinics and contribute to disruptions in continuity of care [2]. Migrant patients frequently arrive without complete medical records or consistent screening histories, complicating cancer detection and follow-up [7]. Mobile patients are also less likely to engage in preventive services, with screening rates up to 40% lower than the regional average [9]. The logistical burden includes increased wait times and shortages of vaccines and testing kits [10]. Community health workers in the region report increasing workload intensity and burnout under these pressures [12].

Binational epidemiologic surveillance limitations were dominant in border health reports and policy analyses. Displaced persons, particularly migrants and seasonal workers, often fall outside the scope of national cancer registries due to lack of a permanent address or documentation [21]. The absence of standardized data collection tools and interoperable platforms between the U.S. and Mexico was described as resulting in in fragmented reporting [8]. For example, cancer cases diagnosed in Mexico but treated in U.S. clinics are rarely tracked systematically in either country [2]. Moreover, there is no shared patient identifier across border systems, complicating continuity of care and follow-up [24]. In some regions, over 40% of patients receive care in both countries but are counted only in one registry, which may contribute to underreporting [25]. Limited cross-agency collaboration and incompatible definitions of health indicators further impair real-time monitoring of incidence and mortality trends. Public health initiatives such as Healthy Border 2030 have emphasized improved binational data coordination, yet operational and political barriers have been described as limiting real-time surveillance integration [26].

Across the 12 included sources, insurance and financial barriers were among the most frequently cited determinants of inequitable cancer outcomes in border communities, followed by language barriers/reduced health literacy, care fragmentation/mobility and policy/governance. Screening infrastructure limitations, including equipment shortages and limited preventive capacity, were regularly documented in clinical and public health analyses [10]. Workforce shortages and constrained oncology specialist access were also recurrent themes in institutional assessments of border-region health systems [12].

Environmental and occupational carcinogen exposure emerged as a distinct but less frequently quantified domain, primarily supported by observational and environmental health reports [8]. Clinical trial access disparities were addressed in a smaller subset of qualitative and policy-focused studies examining participation patterns among Mexican-American populations [22].

Binational surveillance fragmentation and registry underrepresentation were repeatedly identified in governmental and policy documents as substantial epidemiologic gaps that may limit accurate cancer burden estimation [26]. Overall, the evidence base is weighted toward observational and descriptive analyses, with comparatively fewer interventional or longitudinal studies directly evaluating outcomes among displaced border populations [1].

This review has several limitations that warrant consideration. The available evidence base is predominantly observational, descriptive, or qualitative, which may limit causal inference regarding the relationship between migration-related structural factors and cancer outcomes. Few studies employed longitudinal designs or evaluated interventions, and most did not directly measure documentation status, forced displacement, duration of migration, or patterns of cross-border mobility. Instead, many relied on geographic residence, cross-border care utilization, or ethnicity-based proxies to approximate structural vulnerability. While informative, these proxies may underestimate heterogeneity within migrant and displaced populations and limit the precision of comparisons across studies.

In addition, although gray literature searches were structured and targeted, they may have not been fully exhaustive, and some institutional or policy reports were included to provide contextual framing of infrastructure and surveillance gaps. Variability in methodological rigor across sources may influence the strength of certain conclusions. Finally, heterogeneity in study design, populations, and reported outcomes precluded quantitative meta-analysis. As a result, synthesis relied on narrative integration and thematic prevalence mapping rather than pooled effect estimates, and findings should therefore be interpreted as hypothesis-generating rather than definitive.

Cancer inequities among displaced and migrant populations on the U.S.-Mexico border appear to reflect the cumulative effects of structural vulnerability, constrained health system capacity, environmental and occupational risk, research underrepresentation, and fragmented binational surveillance. The evidence synthesized in this review suggests that disparities in screening, stage at diagnosis, survival, and clinical trial participation are not isolated phenomena but are situated within financing models, workforce distribution, mobility-related care disruption, and incomplete cross-border data systems. Although the current literature is largely descriptive, it consistently points to potentially modifiable structural determinants, including insurance gaps, specialist shortages, environmental exposures, and registry fragmentation. Addressing cancer disparities in this region will likely depend on coordinated binational coordination, policy and administrative alignment, investment in preventive and oncology infrastructure, rigorous evaluation of scalable community-based interventions, improved research inclusion, and interoperable surveillance systems capable of capturing mobile populations. Without structural reform that recognizes mobility and transnational care as defining features of the border context, cancer control efforts may remain constrained and inequities may persist.