Apr 28, 2026

Inequalities in cancer treatment in the UK: A scoping review of epidemiological research.

DOI
https://dx.doi.org/10.17504/protocols.io.5qpvoezoxl4o/v1
  • Tetyana Perchyk1,
  • Lizzie Merrill1,
  • Natalie Gil1,
  • Gary Abel2,
  • Eva JA Morris3,
  • Emma Giles4,
  • Elena Finn5,
  • Katie Spencer6,
  • Kate Brain7,
  • Agnieszka Lemanska8,
  • Jenna Bhimani5,
  • Jenny Harris1,
  • Katriina L Whitaker1,
  • Robert Kerrison1
  • 1School of Health Sciences, University of Surrey;
  • 2Univerisity of Exeter Medical School, University of Exeter;
  • 3Big Data Institute & Nuffield Department of Population Health, University of Oxford;
  • 4School of Health and Life Sciences, Teesside University;
  • 5University College London Hospitals;
  • 6Leeds Institute of Health Sciences, University of Leeds;
  • 7Division of Population Medicine, School of Medicine, Cardiff University;
  • 8Scool of Public Health, Faculty of Medicine, Imperial College London
Tetyana Perchyk
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DOI: https://dx.doi.org/10.17504/protocols.io.5qpvoezoxl4o/v1
Protocol Citation: Tetyana Perchyk, Lizzie Merrill, Natalie Gil, Gary Abel, Eva JA Morris, Emma Giles, Elena Finn, Katie Spencer, Kate Brain, Agnieszka Lemanska, Jenna Bhimani, Jenny Harris, Katriina L Whitaker, Robert Kerrison 2026. Inequalities in cancer treatment in the UK: A scoping review of epidemiological research.. protocols.io https://dx.doi.org/10.17504/protocols.io.5qpvoezoxl4o/v1
License: This is an open access  protocol  distributed under the terms of the  Creative Commons Attribution License,  which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited
Protocol status: Working
We use this protocol and it's working
Created: April 28, 2026
Last Modified: April 28, 2026
Protocol  Integer ID: 315864
Keywords: Cancer, Oncology, Treatment, Inequality, Disparities, Inequity, Secondary care, Treatment delay, Time to treatment, Treatment adherence, Deprivation, Ethinc minority, Disability, Epidemiology, Scoping review, Curative treatment, inequalities in cancer treatment, adults with cancer, cancer treatment, recommended treatment plan, uk epidemiological literature, treatment plan, using epidemiological design, treatment delay, review of epidemiological research, epidemiological research, epidemiological design, treatment adherence, cancer, treatment receipt, epidemiological literature, mortality, specialist oncologist, evidence for these inequality, subject to inequality, exploring inequality, identifying relevant study, knowledge gaps for future research, scoping review
Funders Acknowledgements:
Cancer Research UK
Grant ID: RCCCEA-Nov24/100001
Abstract
Background. Cancer is a leading cause of mortality in the United Kingdom (UK). Survival is influenced by the treatment a patient receives ('treatment receipt'). This is improved when treatment is initiated early (shorter 'time to treatment') and when the treatment is adherent to the recommended treatment plan ('treatment adherence'). Unfortunately, all three of these aspects are subject to inequalities, with people from marginalised groups being less likely to receive treatment, more likely to wait longer to start treatment, and less likely to adhere to treatment. The evidence for these inequalities, however, is fragmented, with no reviews synthesising the literature published to date.

Aims. The aims of this review are to: 1) collate, extract and synthesise existing UK epidemiological literature exploring inequalities in cancer treatment, and 2) identify knowledge gaps for future research.

Methods. To address these aims, we are conducting a scoping review, using the six-stage framework described by Arksey and O'Malley, which includes (1) defining the research question, (2) identifying relevant studies, (3) selecting studies, (4) charting the data, (5) synthesising and reporting results, and (6) consulting with stakeholders. The first three stages have been completed already whereas the last three stages have not yet been started. The research question was formulated using the PCC mnemonic: 'Population (adults with cancer), Concept (treatment receipt, treatment delay, or treatment adherence), and Context (UK).' A comprehensive search strategy was developed by incorporating key words and Medical Subject Headings (MeSH) to capture the literature. The search strategy was applied to Web of Science, Embase, Medline, CINAHL and Google Scholar. Articles published ≥2011, available in English, including UK adults treated for cancer, and using epidemiological designs, were deemed eligible. Papers were excluded if they included individuals 3c18 years of age or only explore non-curative treatments. In total, 5,110 unique articles were identified, and 217 passed title and abstract review. These were then narrowed down via full text review to 48 articles considered eligible for inclusion. The included articles will go through data extraction using a data extraction form developed by the authors to facilitate narrative synthesis. All results will be reported in accordance with the PRISMA Extension for Scoping Reviews (PRISMA-ScR) and will be disseminated through a written manuscript detailing the findings. The methods used throughout the scoping review and the interpretation of findings will be reviewed by specialist oncologists.
Introduction
Cancer remains a leading cause of morbidity and mortality in the United Kingdom (UK) [1]. Cancer outcomes, including overall survival, are influenced by the treatments patients receive (‘treatment receipt’) [2–6]. Outcomes are improved when treatment is initiated promptly (shorter ‘time to treatment’) [7–8] and with adherence to the recommended treatment plan (‘treatment adherence’).

However, substantial inequalities have been identified across all three aspects of treatment. These inequalities affect marginalised groups, which are populations or communities experiencing systemic social, political, and economic exclusion that shapes access to resources, services and opportunities. Social determinants of health such as ethnic or socioeconomic inequalities, influence health, generally resulting in worse health outcomes for those from more socially disadvantaged populations [9-10]. For example, individuals from ethnic minority backgrounds are reported to be up to twenty times less likely to receive treatment, and only half as likely to begin treatment within 31 days of diagnosis [11–16].

To date, the evidence base is fragmented, and no published reviews have specifically examined inequalities in cancer treatment in the UK. Two related reviews exist. The first one explored literature focused on the use of data in cancer inequalities research but did not map out treatment inequalities specifically [17]. The second review assessed prior interventions aimed at reducing cancer inequalities, and their effectiveness; however, they did not explore current impacts of inequalities on treatment receipt, time to treatment, or treatment adherence [18].

This scoping review will extend the existing literature by concentrating specifically on inequalities in cancer treatment, synthesising quantitative evidence describing population level inequalities. The review will examine cancer treatments delivered with curative intent, rather than palliative or end-of-life care. This approach enables a focus on inequalities with direct implication for survival and long-term outcomes.
Aims and Objectives
The aim of this review is to synthesise existing UK literature on reported inequalities in cancer treatment receipt, time to treatment, and treatment adherence. The specific objectives are to:

  1. collate, extract and synthesise the existing epidemiological literature exploring inequalities in cancer treatment in the UK;
  2. identify knowledge gaps for future research.
Study Design
The goal of this review is to adopt an epidemiological focus and synthesise quantitative evidence describing population level inequalities in treatment receipt, time to treatment, and treatment adherence. Accordingly, qualitative studies will be excluded because these capture perceived experience rather than objective measures of treatment delivery, and therefore fall outside the scope of this review. A scoping review will be used to address the aims and objectives of this research. This methodology was selected on the basis that scoping reviews are appropriate for a broader topic with less specific research questions [19].

To ensure methodological rigour, the review will follow the six-stage framework previously described by Arksey and O’Malley:

Stage 1. Identifying the research question; Stage 2. Searching for relevant studies; Stage 3. Selecting studies; Stage 4. Charting the data; Stage 5. Collating, summarising and reporting the results; Stage 6. Consultation with stakeholders

The following presents an overview of the approach taken, including work completed to date and planned future work. Stages 1-3 have been completed already, while stages 4, 5 and 6 have not yet commenced.
Stage 1: Identifying the research question (Completed)
We formulated the research question using the PCC mnemonic: ‘Population, Concept, Context’. This allowed us to define the core components of our research question:

Population. Adults ≥18 years diagnosed with cancer
Concept. Inequalities in cancer treatment, time to treatment and treatment adherence
Context. The United Kingdom

The research question was consequently expressed as follows: “Which marginalised groups, in the UK, experience inequalities in cancer treatment receipt, time to treatment and treatment adherence?”
Stage 2: Identifying relevant studies (Completed
To identify studies relevant to our research question, we developed a comprehensive search strategy. We began by curating a list of key words and Medical Subject Headings (MeSH) for each PCC component, using literature known to the authors [17, 18]. Key words and MeSH terms, within components, were then combined using the Boolean Operator ‘OR’, while PCC components were combined through bracketing and use of the Boolean Operator ‘AND’ (wildcards were used to truncate words with multiple suffixes).

The resulting search string was adapted for multiple databases, using their respective syntax. Specifically, the search string was adapted for: Web of Science, Embase, Medline, CINAHL and Google Scholar. These databases were selected in accordance with the method proposed by Bramer and colleagues (2017), who recommend: "reviews should combine Embase, MEDLINE, Web of Science, and Google Scholar (the 200 first relevant references) at minimum” and that “special topic databases, such as CINAHL and PsycINFO, should be added if the topic of the review directly touches the primary focus of a specialized subject database” [20]. The search string used for each database is presented in the Appendix (see Appendices 1-5).

The searches were limited to articles published after 2011. This period was chosen to ensure studies reflected current inequalities in cancer care, following the publication of two landmark policies: i.e. the Equality Act 2010 [21] and the Improving Outcomes: A Strategy for Cancer (2011) [22]).

The results from the searches were exported to Rayyan AI for duplicate removal and screening.
Stage 3: Selection process (Completed
A total of 9,104 articles were identified through Embase and Medline (n=3,519), Web of Science (n=3,700), CINAHL (n=1,685) and Google Scholar (n=200). Of these, 3,994 were duplicates, leaving 5,110 articles eligible for title and abstract review. Title and abstract review was performed independently by four of the authors (TP, EM, NG and RK). To ensure consistency, eligibility criteria were agreed and an initial sample of 250 articles screened by all four authors. Disagreements between authors were resolved through discussion, and the eligibility criteria refined accordingly. A second sample of 100 articles was screened by the same four reviewers, to test the revised criteria. There were no disagreements at this point, so the criteria were not revised further, and the remaining 4,760 articles were divided between the four authors for independent screening (n=1,190 per author).

Following title and abstract review, a total of 217 articles were deemed eligible for full text review. Full text review was performed by two authors (TP and RK), who independently reviewed all 217 articles. Disagreements were discussed between the two authors and, as there were no disagreements that could not be resolved, it was not necessary to arbitrate with additional authors.
Inclusion criteria

Studies were eligible for inclusion based on the following criteria:

  • Primary research

  • Published in peer-reviewed journals

  • Published after 1st January 2011

  • Reported data collected after 1st January 2011

  • Available in English

  • Quantitative or mixed methods (where quantitative data were reported separately)

  • Conducted in the UK

  • Included adults age >18 years

  • Described variation in curative treatment, including surgery, chemotherapy, radiotherapy, hormone therapy, immunotherapy, or any other form of treatment with curative intent.

  • Described variation for treatment receipt, time to treatment and/or treatment adherence
Exclusion criteria.

Studies were excluded if they were:

  • Secondary research

  • Grey literature

  • Published before 1st January 2011

  • Reported data collected prior to 1st January 2011 (studies with data overlapping 2011 [i.e. 2009-2014] were excluded)

  • Unavailable in English

  • Qualitative, Survey, Questionnaire, or any other non-epidemiological study design

  • Conducted outside the UK

  • Included individuals <18 years (studies including both adolescent and adult age groups were excluded)

  • Described variation in treatment with non-curative intent (and curative intent was not reported separately), e.g. palliative treatment, end of life treatment, etc.

  • Did not explore variation in treatment receipt, time to treatment and / or treatment adherence.

A table summarising the eligibility criteria is presented in Appendix 6.
Stage 4: Charting the data
Data describing variations in cancer treatment, including descriptive statistics (e.g. frequencies and percentages), inferential statistics (e.g. odds ratios, confidence intervals and p values), and statistical approaches used (e.g. regression or survival analysis), will be extracted using a tailored data extraction form. The data extraction form that will be used for the study was developed by TP, and reviewed by EM, NG, JH, KW and RK (Appendix 7). The form will be piloted on 5 papers and revised if needed, before being applied to the remaining eligible papers. The data will be charted in a table which will be used to facilitate the narrative synthesis. Contextual data about the studies will also be extracted to aid the interpretation of the statistical data. This will include data relating to cancer type, treatment outcome (e.g. time to treatment), treatment type (e.g. surgery) and treatment stage (e.g. neoadjuvant) (Appendix 7). Any variables relating to an inequality will be identified and extracted. An inequality will be broadly defined as any sociodemographic or personal characteristic that is linked to observed treatment differences. Examples include but are not limited to sex or gender differences, ethnic minority groups (non-white ethnicity), populations identified as most socioeconomically deprived, groups with an identified disability, or any other relevant characteristics reported in the studies. Extraction will include identification of the type of inequality and the measured effect of the inequality on treatment.
Stage 5: Synthesising and reporting results
The overall aim of this scoping review is to identify which marginalised groups have been reported as experiencing inequalities in cancer treatment receipt, time to treatment and treatment adherence, in relation to which cancer types and treatment modalities. This will be achieved through narratives and tables collating the evidence for inequalities, which will simultaneously identify gaps in the literature where future research is needed.

To ensure transparency and reproducibility, the results will be reported in accordance with the PRISMA Extension for Scoping Reviews (PRISMA-ScR) [23]. A PRISMA flow diagram is included in this protocol to illustrate the progress to date. As scoping reviews are iterative, it is possible we will re-run the searches or conduct additional searches, to ensure the results are up to date at the time of publication and relevant articles not omitted (e.g. through backwards and forwards reference list searches).
Stage 6: Consultation with stakeholders
This review forms part of a broader programme of research guided by stakeholder involvement from inception. Consultees, including healthcare professionals (e.g. oncologists) will be identified from existing research projects and clinical networks, and will be consulted throughout the review process to gain insights into the details around treatment modalities, time to treatment and treatment adherence. Their input will also support identification of gaps in the literature, and interpretation and dissemination of clinically meaningful findings.
Dissemination plan
The authors will submit a manuscript for publication in a peer reviewed journal and present their findings at conferences.
Appendices
Download Appendices.docxAppendices.docx93KB

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