Protocol for a hybrid systematic review of the barriers and facilitators to implementing lung cancer screening in community settings.

Access to lung cancer screening

Low-dose computed tomography (LDCT) has emerged as an effective screening tool, supported by robust evidence from large randomised controlled trials (RCTs), including the National Lung Screening Trial (NLST) in the US⁷ and the NELSON study in Europe⁸, which demonstrated a reduction in lung cancer mortality . Building on these findings, many countries have begun to implement lung cancer screening programmes. The European SOLACE initiative aims to support EU member states in optimising LDCT screening under Europe’s Beating Cancer Plan, providing frameworks to address health inequalities and ensure cost-effectiveness⁹.

In 2022, the UK National Screening Committee recommended LDCT for lung cancer screening, based on evidence demonstrating reduced mortality. The comprehensive screening pathway, including identification, invitation, and participation, represents a significant step towards the nationwide implementation of targeted screening. While this initiative is clinically promising, challenges remain regarding its feasibility and implementation. The UK has led efforts to address these challenges through pilot programmes, clinical studies, and the NHS England Targeted Lung Health Check Programme¹⁰.

Equity challenges in implementation

Participation in lung cancer screening remains low, with disparities based on socioeconomic status, smoking history, and ethnicity. Studies show participation rates as low as 1.9% among eligible individuals¹⁰. Barriers include limited awareness of screening benefits, concerns about LDCT radiation, fear of diagnosis, and challenges in risk communication¹⁰. Additional obstacles include practical issues such as cost, travel, and time constraints, as well as healthcare system-level barriers like the need for shared decision-making by healthcare providers¹¹. Socioeconomic disparities, cultural factors, and literacy issues further impede screening uptake, necessitating tailored, culturally sensitive interventions¹².

This hybrid systematic review aims to explore the barriers and facilitators to implementing lung cancer screening, emphasising equitable and informed participation as essential for successful screening uptake. Previous systematic reviews have highlighted the complexities involved, noting the variability of barriers and facilitators across different populations, healthcare systems, and settings^7,10,11. This review will extend current evidence by using an implementation science approach to identify factors affecting screening participation.

The Lung Cancer Policy Network has developed an implementation toolkit to support screening initiatives (refer to extended data Table 1). While useful, a hybrid systematic review can enhance its application by incorporating up-to-date evidence and addressing specific contextual factors, ensuring a more tailored approach to community-based lung cancer screening.

Aims and objectives 

This hybrid systematic review, guided by the Consolidated Framework for Implementation Research (CFIR), aims to identify factors influencing the implementation of lung cancer screening in community settings. The objectives are to:

1.  Synthesise qualitative and quantitative evidence on barriers and facilitators to community-based lung cancer screening.

2.  Identify elements that support or hinder screening programme implementation in various contexts.

3.  Propose strategies to enhance screening participation in community settings.

Provide actionable, evidence-based recommendations to improve global lung cancer screening effectiveness and uptake.

Design

This hybrid systematic review will be conducted in two phases. Phase 1 involves a comprehensive search and extraction of relevant primary studies from previously published systematic reviews on lung cancer screening. Phase 2 aims to identify and include additional individual studies published outside the timeframe of Phase 1 reviews. This two-stage approach is designed to maximise existing evidence while minimising research waste and duplication. Both phases will consider quantitative, qualitative, and mixed-method reviews. The methodology aligns with the guidance of Doyle et al.^13–16, Cochrane guidelines for overviews of reviews (Box 1, Box 2), and the Joanna Briggs Institute (JBI) umbrella review standards (Box 3, Box 4))^17,18. The development of this protocol also follows the PRISMA-P guidelines (Box 5)¹⁹.

Protocol and registration

The protocol will be registered with PROSPERO, the international prospective register of systematic reviews²⁰.

Eligibility criteria

Eligibility criteria are informed by the SPIDER(s) framework, which addresses the Sample, Phenomenon of Interest, Design, Evaluation, Research Type, and Setting of included studies²¹. The added 'Setting' criterion is to ensure contextually relevant studies are included. Reviews or meta-analyses will be eligible if they:

Studies are limited to English-language systematic reviews and meta-analyses published in peer-reviewed journals. Exclusions include editorials, scoping reviews, expert opinions, and narrative reviews. The strategy for identifying systematic reviews and primary studies differs between Phase 1 and 2, as outlined in Table 2 (refer to extended data).

Sample. The review targets two key populations: (1) adults who are eligible or have participated in lung cancer screening programmes (including their families and caregivers) and (2) stakeholders responsible for implementing the screening (e.g., healthcare professionals, community health workers, administrators, and policymakers). The inclusion of both groups provides a comprehensive understanding of potential barriers and facilitators from multiple perspectives.

Phenomenon of interest. The review will focus on the implementation of lung cancer screening in community settings, examining processes such as recruitment, engagement, and participation. Key actions include initial contact and information dissemination, scheduling, reminder systems, educational interventions, counselling, tracking of screening outcomes, and referral pathways for positive results.

Design and evaluation. The review will encompass empirical studies utilising various methodologies. In Phase 1, systematic reviews and meta-analyses will be included, with exclusions applying to protocols, scoping reviews, and non-systematic summaries. In Phase 2, primary studies that explore recruitment strategies for lung cancer screening in community settings will be assessed, with emphasis on identifying barriers and facilitators at the individual, healthcare service, and system levels.

Research type and setting. The review will incorporate quantitative, qualitative, and mixed-method studies. Grey literature will not be included due to the anticipated wealth of existing evidence. The setting criterion focuses on community-based screening, ensuring that studies from primary care and similar environments are eligible. Studies conducted in hospital-based environments, such as radiology departments, medical centres, or long-term care facilities, will be excluded. The rationale is based on evidence indicating the effectiveness of community-based recruitment strategies in increasing participation.

Search strategy

The two-phase search strategy, developed in collaboration with a healthcare librarian, will systematically explore databases starting from January 1, 2000, consistent with the emergence of LDCT as a screening modality. Phase 1 involves a comprehensive search for systematic reviews across databases, including The Cochrane Library, Embase, PubMed, PsycINFO, Scopus, and CINAHL, and will involve citation searching and reference list reviews. The time period from January 1, 2000, to October 1, 2023, reflects the evolving landscape of lung cancer screening. Phase 2 will involve an updated search for primary studies not covered in Phase 1, using a tailored search strategy for each database. Studies reporting on screening strategies will be included, with exclusions for narrative reviews, commentaries, conference abstracts, and recruitment surveys.

Screening and selection

Titles and abstracts will be screened by two independent reviewers, followed by full-text reviews to confirm eligibility. Discrepancies will be resolved by consensus or consultation with a third reviewer. The same process will be applied in both phases (Figure 1).

Figure 1. Illustrates a two-stage process for the identification of primary studies.

Quality assessment

We will evaluate the quality of the primary studies extracted from the eligible systematic reviews using the assessments provided in the reviews, where available. In the event that different tools are employed, we will integrate them by conducting the MMAT assessment²² on all studies that lack this evaluation. We will independently analyse the risk of bias using the Mixed-method Appraisal Tool (MMAT) and two reviewers, if the quality of a research has not been evaluated in the review or if our own personal search finds the study not to be part of the systematic reviews²². While quality assessment will inform the interpretation of findings, studies will not be excluded solely based on quality. Sensitivity analyses will be conducted focusing on high-quality studies.

Data synthesis

Data will be synthesised thematically, guided by the Consolidated Framework for Implementation Research (CFIR)²³. Identified facilitators and barriers will be categorised into CFIR’s five domains: intervention characteristics, external environment, internal setting, characteristics of individuals involved, and the implementation process (refer to extended data Table 3). A mixed-method synthesis will integrate both qualitative and quantitative data, providing a comprehensive understanding of the factors influencing lung cancer screening uptake. Qualitative data will be coded and, where appropriate, translated into a numerical format for thematic weighting.

Confidence in cumulative evidence

The reliability of evidence will be evaluated using the GRADE and CERQual tools^24,25. This assessment will cover methodological limitations, relevance, coherence, and adequacy, providing a clear indication of the quality and confidence of the findings.

Potential limitations

While the review is designed to be comprehensive, there are certain limitations. First, restricting the search to English-language publications may introduce language bias, potentially overlooking insights from non-English studies. Existing research suggests that this could limit the applicability of findings, especially in multilingual communities or low-resource settings where language and culture significantly influence healthcare behaviours²⁶. Nonetheless, given the practical challenges of translation and the predominance of high-quality scientific literature in English, the scope remains appropriate for our objectives.

Second, by excluding less rigorous study designs such as narrative reviews, editorials, and opinion pieces, the review may miss some relevant discussions and hypotheses that have not yet been substantiated through systematic research. However, prioritising systematic reviews and meta-analyses is a deliberate choice to ensure that our synthesis is grounded in the highest levels of evidence, which is vital for producing robust, actionable recommendations²⁷.

Lastly, there may be variability in how barriers and facilitators are conceptualised and reported across studies, given the diversity of settings and methodologies involved. This heterogeneity can pose challenges for data synthesis and may limit the generalisability of findings²⁸. However, using CFIR as an organising framework will allow us to systematically categorise and interpret these diverse factors, providing a cohesive narrative of implementation challenges and enablers.

Implications and future directions

The review’s findings will offer valuable guidance for healthcare practitioners, researchers, and policymakers to develop and implement more effective lung cancer screening strategies in community settings. Specifically, by identifying and understanding barriers—such as limited knowledge about screening, concerns over radiation risks, and socioeconomic disparities—we can inform culturally sensitive and patient-centred interventions. Evidence from previous studies, including qualitative research on patient perceptions and healthcare provider attitudes, highlights the importance of addressing these multifaceted challenges to improve engagement and uptake²⁹.

Furthermore, understanding facilitators like supportive policies, effective communication strategies, and the involvement of community health workers can guide the development of interventions that are more tailored and responsive to specific community needs. The review's emphasis on a range of contexts will provide insights applicable to varied healthcare systems, from highly resourced environments to those facing significant logistical challenges in screening implementation²⁹. These insights will help bridge gaps in participation and ensure that lung cancer screening is both equitable and accessible, particularly for underserved populations.

Integration with current evidence

The potential of LDCT screening to reduce lung cancer mortality has been well-documented in trials such as the National Lung Screening Trial (NLST) and the NELSON study, leading to the endorsement of screening programmes in several countries^7,30. However, real-world implementation faces considerable challenges, as low participation rates and inequities in access persist. Previous systematic reviews have explored barriers at the individual and system levels, but a comprehensive review through an implementation science lens is crucial for translating research into practice effectively⁸.

Our review will build upon the existing literature by specifically addressing the complexities of community-based screening. The CFIR-guided thematic synthesis will allow for a structured analysis of how intervention characteristics, outer and inner settings, individual factors, and implementation processes interact to affect lung cancer screening uptake. This approach is expected to reveal critical leverage points for enhancing programme design, training healthcare professionals, and developing policy initiatives.

Future research and practice

While this review will provide a foundational understanding of the barriers and facilitators to community-based lung cancer screening, further research will be necessary to translate these insights into effective strategies. For instance, implementation studies that tailor interventions to specific community contexts are needed to evaluate their real-world effectiveness and feasibility³¹. Additionally, as emerging technologies and evidence evolve, there will be an ongoing need to refine and update screening strategies to maintain their relevance and impact.

Overall, this review will contribute to the advancement of lung cancer screening by providing actionable, evidence-based recommendations. These insights can inform the design of equitable and sustainable screening programmes that are responsive to the needs of diverse communities, ultimately improving early detection and outcomes in lung cancer care.