An investigation of routes to cancer diagnosis in 10 international jurisdictions, as part of the International Cancer Benchmarking Partnership: survey development and implementation
David Weller1 (Corresponding author)
Postal Address: Centre for Population Health Sciences, University of Edinburgh, Medical School, Teviot Place, Edinburgh EH8 9AG
Email:
Peter Vedsted2
Email:
Chantelle Anandan1
Email:
Alina Zalounina2
Email:
Evangelia Ourania Fourkala3
Email:
Rakshit Desai3
Email:
William Liston3
Email:
Henry Jensen2
Email:
Andriana Barisic4
Email:
Anna Gavin5
Email:
Eva Grunfeld6
Email:
Mats Lambe7
Email:
Rebecca-Jane Law8
Email:
Martin Malmberg9
Email:
Richard D Neal8
Email:
Jatinderpal Kalsi3
Email:
Donna Turner10
Email:
Victoria White11
Email:
Martine Bomb12
Email:
Usha Menon3
Email:
ICBP Module 4 Working Group*
Email:
1 Centre for Population Health Sciences, University of Edinburgh, Edinburgh, United Kingdom,
2 Research Unit for General Practice, Department of Public Health, Aarhus University, Denmark
3 Gynaecological Cancer Research Centre, Women's Cancer, Institute for Women's Health, University College London, United Kingdom
4Department of Prevention and Cancer Control, Cancer Care Ontario, Toronto, Ontario, Canada
5 Northern Ireland Cancer Registry, Centre for Public Health, Queen's University Belfast, Belfast, United Kingdom
6Knowledge Translation Research Network Health Services Research Program, Ontario Institute for Cancer Research
Department of Family and Community Medicine, University of Toronto, Toronto, Ontario, Canada
7 Regional Cancer Center Uppsala and Department of Medical Epidemiology and Biostatics, Karolinska Institutet, Stockholm, Sweden
8 North Wales Centre for Primary Care Research, Bangor University, Wrexham, United Kingdom
9 Department of Oncology, Lund University Hospital, Lund, Sweden
10 Population Oncology, Cancer Care Manitoba, 675 McDermot Street, Winnipeg, Manitoba, Canada
11 Centre for Behavioral Research in Cancer, Cancer Council Victoria, Melbourne, Victoria, Australia
12 Policy and Information, Cancer Research UK, London, United Kingdom
Keywords: General practice; Primary Health care; Time factors, Diagnosis; Early Detection of Cancer; Health Services Research
To cite: Weller D, Vedsted P, Anandan C, et al. An investigation of routes to cancer diagnosis in 10 international jurisdictions, as part of the International Cancer Benchmarking Partnership: survey development and implementation. BMJ Open 2016;6:e009641. doi:10.1136/bmjopen-2015-009641
Prepublication history and additional material is available. To view please visit the journal (http://dx.doi.org/10.1136/bmjopen-2015-009641).
Abstract
Objectives
This paper describes the methods used in the International Cancer Benchmarking Partnership Module 4 Survey (ICBPM4) which examines time intervals and routes to cancer diagnosis in 10 jurisdictions. We present the study design with defining and measuring time intervals, identifying patients with cancer, questionnaire development, data management and analyses.
Design and setting
Recruitment of participants to the ICBPM4 survey is based on cancer registries in each jurisdiction. Questionnaires draw on previous instruments and have been through a process of cognitive testing and piloting in three jurisdictions followed by standardised translation and adaptation. Data analysis focuses on comparing differences in time intervals and routes to diagnosis in the jurisdictions.
Participants
Our target is 200 symptomatic breast, lung, colorectal and ovarian cancer patients in each jurisdiction. Patients are approached directly or via their primary care physician (PCP). Patients’ PCPs and cancer treatment specialists (CTSs) are surveyed, and ‘data rules’ are applied to combine and reconcile conflicting information. Where CTS information is unavailable, audit information is sought from treatment records and databases.
Main outcomes
Reliability testing of the patient questionnaire, showed agreement was complete (Kappa=1) in four items and substantial (Kappa=0.8, 95%CI: 0.333-1) in one item. The identification of eligible patients is sufficient to meet the targets for breast, lung and colorectal cancer. Initial patient and PCP survey response rates from the UK and Sweden are comparable with similar published surveys. Data collection was completed in early 2016 for all cancer types.
Conclusion
An international questionnaire-based survey of cancer patients, PCPs and CTSshas been developed and launched in 10 jurisdictions. ICBPM4 will help to further understand international differences in cancer survival by comparing time intervals and routes to cancer diagnosis.
Strengths and limitations of this study
· There are no previous examples of applying standardised survey methods in a broad range of jurisdictions to examine components of diagnostic intervals in cancer.
· This study could provide unique insights into why cancer survival differences exist in different regions of the world.
· International Cancer Benchmarking Partnership Module 4 Survey is a questionnaire-based survey, and results are subject to limitations and caveats – particularly those arising from non-response bias and external validity.
· Response to a questionnaire on diagnostic journeys in cancer patients may be influenced by factors which differ across jurisdictions, compounding existing non-response bias.
Background
The International Cancer Benchmarking Partnership (ICBP) is a major international collaboration which is exploring differences in cancer survival between Australia, Canada, Denmark, Norway, Sweden and the UK[1]. It has already demonstrated significant differences in 1- and 5-year relative survival for breast, lung, colorectal and ovarian cancers amongst participating jurisdictions[2]. Recent data confirm that significant disparities in cancer survival persist across a range of tumour types in Europe[3]. The ICBP further seeks to systematically explore population and health care-related factors in relation to these variations in cancer survival. Survival differences between populations are most probably due to a range of factors including lifestyle, levels of comorbidity, availability of screening programmes, primary care system, and availability and quality of diagnostic and treatment services[2, 4-7]. Module 4 of the ICBP (ICBPM4) aims to:
· Compare time intervals (patient, primary care, diagnostic and treatment and total intervals – see Figure 1) between jurisdictions.
· Identify the proportion of patients entering the cancer pathway through different routes (e.g. symptom-based diagnosis, screening, via accident and emergency (A&E)) and analyse the association with time intervals within jurisdictions.
· Analyse the association between time intervals (outlined in the methods section) and cancer outcomes in participating jurisdictions and identify where actions to reduce delays could be focussed.
The central research question of ICBPM4 is: ‘can variations in cancer survival between jurisdictions participating in the International Cancer Benchmarking Partnership be explained by differences in routes to diagnosis?’ Routes to diagnosis have an important influence on cancer outcomes and patient experience. For common cancers, such as colorectal cancer, available evidence suggests that longer patient intervals (the time from first noticing symptoms to seeking help) are associated with poorer survival[8], and that longer diagnostic intervals (from first presentation until diagnosis) increase mortality[9-12]. There is a growing body of evidence examining the relationship between various components of the diagnostic journey and long-term cancer outcomes; emergency presentation is typically associated with worse patient outcomes, and this negative effect persists after adjustment for stage[13]. Further, while their number of pre-diagnosis consultations has not been quantified, qualitative evidence suggests that patients who present as emergencies typically have prolonged, circuitous pathways, in which consultations are not necessarily a conduit to diagnosis[14]. There is some observational evidence that prolonged primary care time intervals can adversely affect outcomes, and similar associations are found with longer treatment intervals[15], although evidence across a range of cancers is mixed[12]. In terms of patient experience, it’s known that patients prioritise rapid investigation for cancer[16], and ‘time to diagnosis’ affects patients’ confidence in the health care system[17]. Hence, investigating differences in routes to cancer diagnosis between different countries can help in assessing the possible impact on cancer survival.
Accordingly, there is a great deal of interest in shortening diagnostic intervals through better access to investigations, and decision aids in primary care[18,19], as there are some indications that variation in access, and readiness to use, diagnostic investigations might influence cancer outcomes[6,20]; the gatekeeping function in primary care may also influence diagnostic intervals[21]. Longer diagnostic intervals may lead to cancers which are more advanced at the time of diagnosis; there is some evidence, for example, of later stage diagnoses in the UK compared to other countries, notably for lung and colorectal cancers[22, 23]. Further, treatment intervals have been shown to be associated with stage progression[24,25].
ICBP Module 1 showed that cancer survival is higher in Sweden, Canada and Australia, intermediate in Norway and lower in Denmark and the UK[2]. Further analysis in Module 1 suggests that differences in treatment and access to optimal treatment may be impacting on survival outcomes, alongside evident ‘delays’ in diagnosis[4,26]. ICBP Module 2 demonstrated that awareness and beliefs about cancer are unlikely to explain international survival differences but may form part of a more complex picture[5]. ICBP Module 3 compared primary care systems and found differences in PCP readiness to investigate between countries that could be related to cancer outcomes[6]. Given the international differences in survival and the scientific basis for the importance of routes to cancer diagnosis and treatment, a detailed examination of international differences in diagnostic pathways is important.
The purpose of this paper is to present the study design (highlighting key issues in defining and measuring milestones and time intervals), and to report on processes of identifying cancer patients, questionnaire development, data management and analyses.
Management of ICBP
The ICBP is overseen by a Programme Board with representatives from all participating jurisdictions. The Board meets regularly to review progress and findings from each of the modules. Dedicated module chairs, overseeing each module, report to the Programme Board. ICBPM4 is led by a central academic team with module co-chairs and senior researchers based at University College London (UCL), UK, the University of Edinburgh, UK and Aarhus University, Denmark. Cancer Research UK provides programme management support to the central team[27]. The ICBPM4 central academic team and the overall programme management are funded jointly by participating jurisdictions. Each of the ICBPM4 jurisdictions has an individual lead and management team to conduct their own local survey. Regular meetings take place between the jurisdiction leads and the central academic team.
ICBPM4 study design
The study is an international, multicentre, cross-sectional, population-based survey of newly diagnosed cancer patients. Ten jurisdictions [Australia (Victoria), Canada (Manitoba, Ontario), Denmark, Norway, Sweden and the UK (England, Northern Ireland, Scotland and Wales)] are participating. These jurisdictions were selected as they are considered to be reasonably similar regarding access and expenditure on healthcare and level of cancer treatment but show variation in cancer survival. They all have comprehensive cancer registration facilitating international studies[1].
In common with other ICBP modules[2] four cancers are included – breast, ovarian, colorectal and lung cancer. There is variation amongst these cancers in terms of their symptom characteristics, availability of screening, treatments and effects of other factors like age and co-morbidity. For a given period in each jurisdiction, newly diagnosed cancer patients were identified and a questionnaire was sent to the patient, the PCP and the diagnosing/treating hospital. The questionnaire focused particularly on specific milestones, time intervals and the routes to diagnosis. The study was initiated in 2009 and the data collection launched in 2013. Data collection finished in early 2016.
Routes to diagnosis
An understanding of differences in routes to diagnosis between jurisdictions is important to understand differences in time intervals and where, if feasible, to focus an intervention. Cancers may be diagnosed through routes other than symptomatic presentation to primary care, such as screening, or direct presentation to a specialist or hospital emergency department. The survey sought to capture this variety of diagnostic routes.
It is, nevertheless, difficult to capture complex patient journeys in surveys; the questionnaire drew on previous ‘routes to diagnosis’ research[13] but we refined previous definitions of time-points and intervals, using guidance in the Aarhus Statement[28]. Further, we specified routes to be explored as: 1) symptoms/a bodily change prompting doctor visit; 2) symptoms/a bodily change prompting visit to Accident and Emergency (A&E); 3) combinations of 1) and 2); 4) incidental diagnosis in course of investigation or treatment for another problem; 5) participation in population based cancer screening programme; 6) other route. Using these predefined routes it was possible to standardise data between jurisdictions – it also made our classifications consistent with those used in ICBP Module 3, enabling combination of data with these modules in future analyses[6].
Measuring time-points and intervals
A central aim of ICBPM4 is to measure and compare time intervals (patient, primary care, diagnostic and treatment intervals) in participating jurisdictions. To build on the best existing knowledge and conceptualisation of time intervals, we used the Aarhus Statement[28] (see Figure 1) and focused on four key time-points, defined as shown in Table 1. We sought to define, as precisely as possible, the different time intervals, as measurement of time-points can all present methodological challenges – it’s also necessary to decide which source of data (patient, PCP, CTS) is preferred for each of the time-points, in order to generate data rules when there are multiple sources of information:
· Date of first symptom – cancer symptoms can be multiple, vague and non-specific, making it difficult to precisely identify this date (collected, in ICBPM4, from patient and PCP. Preferred reporting source: patient).
· Date of first presentation to primary care – similarly, it is often difficult to establish which ‘presentation’ in primary care represents the first time a patient seeks help about cancer-related symptoms (collected from patient and PCP. Preferred reporting source: PCP).
· Date of referral – there can be confusion over the date on which the PCP engages specialist diagnostic and treatment services for the patient’s on-going management; in this study we defined date of first referral as the date where the PCP transferred the responsibility for further diagnosis and treatment to specialist services (collected from PCP).
· Date of diagnosis – a range of definitions exist, including dates of 1) tissue diagnosis and 2) receiving results of investigations. Therefore, respondents were asked to report date of diagnosis and, additionally, what they based their understanding of date of diagnosis on (collected from patient, PCP and CTS. Preferred reporting source: CTS > PCP > patient)
Figure 1. Key time-points and diagnostic intervals in the route from first symptom until start of treatment[28 ,36]