Cervical Cancer Prevention and Treatment Disparities Among Native Hawaiian and Pacific Islanders: A Systematic Review and Meta-Analysis.

1
Introduction
Cervical cancer remains a significant public health concern, disproportionately affecting underserved and minority populations worldwide [1]. While rates of cervical cancer incidence and mortality have declined in many high‐income countries due to the widespread implementation of Pap testing and HPV vaccination, persistent disparities exist among specific racial and ethnic groups in the United States [2, 3, 4]. Native Hawaiian and Pacific Islander (NHPI) populations represent a particularly vulnerable group, with unique cultural, geographic, and systemic barriers contributing to lower rates of cervical cancer prevention, delayed treatment, and worse outcomes [5].
Despite their recognized vulnerability, NHPI populations are often underrepresented in research, with data frequently aggregated under broader Asian American categories [6]. This lack of disaggregated data obscures the disparities faced by NHPI communities, which differ substantially from other racial and ethnic groups. For instance, NHPI women are less likely to receive Pap testing or HPV vaccination compared to non‐Hispanic White (NHW) women, and they experience higher rates of late‐stage cervical cancer diagnosis and mortality [7]. Compounding these challenges are systemic issues such as geographic isolation, limited healthcare access, and cultural stigma, which further hinder efforts to address these disparities.
Efforts to improve cervical cancer prevention and treatment outcomes for NHPI populations require a nuanced understanding of their unique barriers and facilitators [8]. Culturally tailored interventions, such as community‐based participatory research (CBPR) and educational campaigns, have shown promise in addressing some of these challenges [9]. However, significant gaps remain in the literature regarding the effectiveness of these strategies and their scalability across diverse NHPI subgroups.
This systematic review and meta‐analysis aims to comprehensively evaluate the current state of cervical cancer prevention and treatment among NHPI populations. Specifically, it examines rates of Pap testing and HPV vaccination, explores disparities in treatment and outcomes, and synthesizes evidence on effective interventions. By highlighting key findings and areas for improvement, this study seeks to inform targeted public health strategies to reduce cervical cancer disparities in this underserved population.

2
Methods
This systematic review and meta‐analysis was conducted following PRISMA (Preferred Reporting Items for Systematic Reviews and Meta‐Analyses) guidelines to ensure transparency and rigor. The protocol was registered with PROSPERO (International Prospective Register of Systematic Reviews) under registration number CRD42024628364. A comprehensive search was performed across three databases—PubMed, Scopus, and Embase—to identify studies reporting cervical cancer prevention metrics, including Pap testing rates, HPV vaccination rates, and treatment outcomes among NHPI populations (Figure 1).
Searches were limited to articles published in English from January 2000 to December 2024. In PubMed, terms such as (“Cervical Cancer” [MeSH] OR “Pap Smear” [MeSH] OR “HPV Vaccines” [MeSH]) AND (“Native Hawaiian” OR “Pacific Islander” OR “NHPI” OR “Indigenous Pacific” OR “Polynesian”) were used, while similar strings adapted for Scopus and Embase ensured comprehensive coverage.
Studies were eligible for inclusion if they reported Pap testing or HPV vaccination metrics for NHPI populations or provided disaggregated data for NHPI subgroups. Both quantitative and qualitative study designs, including cross‐sectional, cohort, and randomized controlled trials (RCTs), were considered. Studies published as abstracts, commentaries, or letters without primary data and those that aggregated NHPI populations with other groups without disaggregation were excluded.
Two independent reviewers screened titles and abstracts, followed by full‐text reviews of potentially relevant studies. Any disagreements were resolved through discussion or consultation with a third reviewer. Data extraction was performed using a standardized form to collect information on study characteristics (e.g., author, year, study design, sample size), population demographics, and outcomes such as Pap testing rates, HPV vaccine initiation/completion rates, and treatment metrics.
The quality of included studies was assessed using validated tools appropriate to each study design: the Joanna Briggs Institute (JBI) checklist for cross‐sectional studies, the Newcastle‐Ottawa Scale for cohort studies, and the Cochrane Risk of Bias Tool for RCTs (Table 1). Meta‐analyses were performed for Pap testing and HPV vaccine initiation rates using a random‐effects model to account for variability across studies. Heterogeneity was assessed using the I² statistic and Cochran's Q test. For studies unsuitable for meta‐analysis, a narrative synthesis was conducted, highlighting key findings and contextual insights. All analyses were conducted using the meta package in R software. Sensitivity analyses and publication bias assessments were not pursued due to limited number of eligible studies with necessary race and ethnicity data. While these results would positively impact the robustness of our analyses, limitations in data availability prohibit our ability to broaden our report.

3
Results
A comprehensive narrative synthesis was conducted, incorporating all 27 studies that addressed cervical cancer prevention metrics such as Pap testing rates, HPV vaccination uptake, and treatment outcomes. These studies highlight persistent disparities in cervical cancer prevention and care among Native Hawaiian and Pacific Islander (NHPI) populations and emphasize the importance of targeted, culturally tailored interventions (Table 2).
3.1
Pap Testing Rates
Pap testing rates were generally suboptimal across studies, with significant variability. Chen et al. reported that 72% of NHPI women in Los Angeles County had undergone a Pap test, a rate lower than non‐Hispanic White (NHW) women (81%) but higher than some other Asian subgroups, such as Chinese (56%) and Korean (65%) [10]. Similarly, McDaniel et al. observed that NHPI women were significantly less likely to have received a Pap test compared to NHW women (adjusted OR: 0.339) [11]. Despite improvements in Pap testing rates among NHPI women between 2014 and 2018 (from 73.95% to 82.98%), disparities persisted compared to other groups.
Aitaoto et al. highlighted the barriers specific to Chuukese and Marshallese women in Hawaii, where only 33% reported access to Pap tests compared to 93% of Native Hawaiian women [12]. Weiss et al., Tanjasiri et al. (2012), and Mouttapa (2016) found that emotional and informational support from family members significantly influenced Pap testing behavior, with Tongan women reporting disproportionately lower screening rates compared to other Pacific Islander subgroups [13, 14, 15].
Interventions have been shown to improve Pap testing rates in specific NHPI communities. Tanjasiri et al. (2019) demonstrated that community‐based social support interventions significantly increased Pap testing rates, from 40.2% in the control group to 55.4% in the intervention group [16]. Similarly, Tran et al. found that women who sought advice from healthcare providers were significantly more likely to complete screening (AOR = 12.12, p = 0.033) [17]. Novinson et al. found that an educational intervention in the US‐Associated Pacific Island Jurisdictions increased knowledge about cervical cancer and HPV risks, which likely translated into improved screening behaviors [18].

3.2
HPV Vaccination Rates
HPV vaccination rates were consistently low across NHPI populations, with significant barriers identified in multiple studies. Gopalani et al. reported an HPV vaccine initiation rate of 24.9% among NHPI adults aged 18–26, with completion rates as low as 11.5% [19]. Gender disparities were evident, with women having 5.4 times higher odds of initiating vaccination than men. Dela Cruz et al. (2020) found that 35.2% of NHPI adolescents in Hawaii initiated HPV vaccination, but barriers included a lack of physician recommendations and limited knowledge [20].
Cultural stigma and misconceptions about the vaccine were recurring themes. Fok et al. found that 40% of NHPI parents associated the vaccine with taboo topics, while Mouttapa et al. (2023) highlighted concerns about reproductive health and vaccine side effects [21, 22]. Schisler et al. added an important dimension by identifying that the nonavalent HPV vaccine could protect against up to 88% of HPV‐related cancers in NHPI populations, underscoring the potential impact of improving vaccination rates [23].
Interventions have shown promise in addressing these barriers. Dela Cruz et al. (2017) reported that culturally tailored educational materials and physician recommendations significantly improved parental willingness to vaccinate their children [24]. Similarly, Novinson et al. demonstrated that targeted educational campaigns increased HPV vaccination intentions from 81% to 95% (p = 0.0039) in underserved NHPI communities [18].

3.3
Cervical Cancer Treatment and Outcomes
Disparities in cervical cancer treatment and outcomes were consistently documented. Lee et al. found that NHPI patients with locally advanced cervical cancer were less likely to receive care at high‐volume facilities (22% compared to 33% for Asian Americans overall) and experienced the longest delays in treatment initiation (39% starting after 8 weeks) [25]. Sitler et al. reported that NHPI patients treated through the Pacific Island Health Care Project (PIHCP) had higher adherence to standard‐of‐care radiation therapy (71.6%) compared to the U.S. average (49.5%) [26].
Disaggregated data further highlighted disparities among NHPI subgroups. Ho et al. found that NHPI women were 1.58 times more likely to present with metastatic cervical cancer compared to NHW women (aOR: 1.58, p = 0.001) [27]. Pacific Islanders had disproportionately high rates of advanced‐stage disease. Robison et al. also found that Pacific Islanders diagnosed with cervical cancer had significantly worse 5‐year survival rates (32%) compared to NHW women (71%) [28].

3.4
Barriers and Facilitators
Barriers to cervical cancer prevention in NHPI populations included systemic, cultural, and individual factors. Systemic barriers include limited healthcare access, physician recommendations, and geographic isolation, as seen in studies like Lee et al. and Sitler et al. [25, 26]. Cultural barriers include misconceptions about cervical cancer and HPV, as well as cultural stigma, which were noted in studies such as Fok et al. and Schisler et al. [21, 23]. However, some studies presented interventions to combat these barriers, including community‐based participatory research (CBPR) approaches, culturally tailored educational interventions, and strong social support networks, that were effective in addressing barriers. Studies such as Tanjasiri et al. (2015) and Gotay et al. demonstrated the value of leveraging culturally relevant outreach to improve screening and vaccination rates [29, 30].

3.5
Meta‐Analysis of Pap Testing Rates
The meta‐analysis included six studies that reported Pap testing rates among NHPI populations. These studies varied in design and population sizes, ranging from 14 participants in Chen et al. to 1184 participants in McDaniel et al. [10, 11]. The pooled estimate of Pap testing rates was 62% (95% CI: 46%–75%) using a random‐effects model, reflecting moderate uptake among NHPI populations. Significant heterogeneity was observed (I² = 98.7%, p < 0.0001) (Figures 2 and 3).

3.6
Meta‐Analysis of HPV Vaccine Initiation Rates
The meta‐analysis included four studies reporting HPV vaccine initiation rates among NHPI populations. These studies encompassed a range of geographic and demographic contexts, with sample sizes varying from 70 participants in Kepka et al. to 1204 participants in Gopalani et al. [19, 31]. The pooled estimate for HPV vaccine initiation was 25% (95% CI: 16%–37%) under the random‐effects model, reflecting significant room for improvement in vaccine uptake among NHPI populations. High heterogeneity was observed (I² = 84.3%, p < 0.001), indicating considerable variability across studies (Figures 4 and 5).

4
Discussion
The findings of this comprehensive synthesis and meta‐analysis elucidate the profound disparities in cervical cancer prevention, vaccination, and treatment among NHPI populations. While the results affirm the existence of systemic, cultural, and logistical barriers, they also reveal nuanced interplays between these factors, warranting a deeper analysis to inform actionable strategies.
4.1
Pap Testing Rates
The pooled Pap testing rate of 62% among NHPI populations falls significantly short of the U.S. national average (~80%), underscoring persistent gaps in preventive care [32]. This shortfall not only highlights inequities but also signals a broader structural issue in the integration of NHPI populations into preventive healthcare systems. Despite some gains in national datasets such as the Behavioral Risk Factor Surveillance System (BRFSS) reported by McDaniel et al., the variability across studies (e.g., 40.2% in Tanjasiri et al. (2019) vs. 72% in Chen et al.) suggests that geographic and cultural contexts critically shape outcomes [10, 11, 16].
Barriers to Pap testing among NHPI populations often intersect with structural and cultural determinants. Geographic isolation in Pacific territories limits access to screening facilities, exacerbated by economic disparities that hinder travel to urban centers [25]. Additionally, cultural perceptions of modesty, family shame, and mistrust of healthcare providers further impede screening, as seen in Chuukese women, whose Pap testing rate was as low as 33% [12]. These barriers are distinct from those seen in other racial groups, where logistical and socioeconomic challenges often dominate; for example, African American women cite financial and time constraints more frequently than cultural stigma as impediments to screening [33].
The success of community‐based participatory research (CBPR) approaches and culturally tailored interventions in improving Pap testing rates highlights the importance of culturally congruent strategies. For example, Tanjasiri et al. (2019) demonstrated a 15% increase in screening rates using social support networks, while Tran et al. showed that direct advice from healthcare providers significantly increased uptake [15, 16]. These findings align with interventions in other underserved populations, such as the use of promotoras (lay health workers) in Hispanic communities, emphasizing the transferability of CBPR principles across cultural contexts [34].

4.2
HPV Vaccination Rates
HPV vaccination rates among NHPI populations are alarmingly low, with a pooled initiation rate of 25%. This figure contrasts starkly with national averages (~50% for initiation in adults aged 18–26 and ~60% among adolescents). The disparities become even more pronounced when compared to Hispanic and African American adolescents, whose vaccination rates have shown steady improvement due to targeted public health campaigns [35]. The NHPI‐specific gap, therefore, underscores a lack of focused interventions addressing unique cultural and systemic barriers.
The findings from Fok et al. and Mouttapa et al. (2023) illuminate how deeply rooted cultural factors exacerbate these disparities [21, 22]. Misconceptions linking HPV vaccination to promiscuity, coupled with fears of vaccine‐induced infertility, reflect broader cultural taboos around reproductive health in NHPI communities. These barriers are less frequently observed in other minority groups, where concerns tend to center around cost and access rather than cultural stigma [36]. This suggests that interventions for NHPI populations must go beyond generic education campaigns to directly address culturally specific fears and misconceptions.
The potential of HPV vaccination to significantly reduce cervical cancer incidence cannot be overstated. Schisler et al. demonstrated that the nonavalent vaccine could prevent up to 88% of HPV‐related cancers in NHPI populations, compared to just 28% preventable with earlier quadrivalent vaccines [23]. The stark contrast between the potential efficacy of vaccination and the current low uptake highlights a missed opportunity for cancer prevention. Novinson et al. and Dela Cruz (2020) illustrate that culturally tailored materials and healthcare provider recommendations can improve vaccine uptake, but these efforts require scalability and integration into broader public health strategies [18, 20].
While NHPI‐specific disparities are significant, the US as whole has fairly comparable rates of HPV vaccination as other developed nations [37]. Additionally, the US has high overall Pap screening rates when compared to many countries, but lags specifically in populations that are foreign‐born, have lower socioeconomic status, or are from certain racial or ethnic groups [38]. Future targeted endeavors focused on the NHPI population would likely benefit other communities that similarly have lower rates of vaccination and screening.

4.3
Cervical Cancer Treatment and Outcomes
NHPI women face profound disparities in cervical cancer treatment, from delayed care to poor survival outcomes. For example, Lee et al. found that only 22% of NHPI women received care at high‐volume facilities compared to 33% of aggregated Asian American populations [25]. Such discrepancies mirror findings in African American populations, where treatment at low‐volume facilities correlates with poorer survival [39, 40]. The delays in treatment initiation reported by Lee et al. (39% starting after 8 weeks) further compound these disparities, aligning with evidence that treatment delays directly increase mortality risk in cervical cancer patients [25].
The 5‐year survival rate of 32% reported by Robison et al. for Pacific Islanders starkly contrasts with the 71% rate for NHW women [28]. This disparity, while attributable in part to late‐stage presentation, also reflects systemic inequities in healthcare access and quality [26]. Studies in other minority groups have shown that addressing socioeconomic determinants, such as insurance coverage and geographic access, can improve outcomes. However, the intersectionality of barriers NHPI populations face—including cultural stigma, mistrust of the healthcare system, and geographic isolation—requires a more nuanced approach.
Programs like the Pacific Island Health Care Project (PIHCP), which improved adherence to standard‐of‐care radiation therapy, demonstrate that targeted healthcare delivery models can mitigate some of these disparities [26]. However, the scalability of such programs remains a challenge, particularly given the resource constraints in many Pacific Island territories.

5
Limitations and Future Directions
This study's limitations include high heterogeneity in meta‐analyses, small sample sizes, reliance on self‐reported data, and the predominance of cross‐sectional designs, which restrict causal inferences and generalizability. Future research should prioritize disaggregated analyses of NHPI subgroups, longitudinal studies to assess the long‐term impact of interventions, and integration of culturally tailored strategies into national public health programs. Policy advocacy should address systemic inequities, such as limited access to high‐volume care and healthcare shortages in Pacific territories, to reduce disparities and improve cervical cancer outcomes for NHPI populations.

6
Conclusion
NHPI populations face significant disparities in cervical cancer prevention, vaccination, and treatment, driven by systemic, cultural, and individual barriers. While culturally tailored interventions demonstrate potential, addressing these disparities requires a multifaceted approach, integrating disaggregated research, targeted policy changes, and scalable community‐based programs. These findings emphasize the urgent need for equity‐focused strategies to reduce the burden of cervical cancer in this underserved population.

Consent
The authors have nothing to report.

Conflicts of Interest
The authors declare no conflicts of interest.

Synopsis
The paper reviews and analyzes disparities in cervical cancer prevention and treatment among Native Hawaiian and Pacific Islander (NHPI) populations, revealing low rates of Pap testing and HPV vaccination due to barriers like healthcare access and cultural stigma. Effective interventions include culturally tailored education and community engagement. The study emphasizes the need for culturally tailored interventions, policy changes, and further research into applicable solutions to improve cervical cancer outcomes for NHPI communities.

Supporting information
PRISMA 2020 checklist 2 2.